Patent Publication Number: US-8534665-B2

Title: Input tray capable of aligning paper

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to input trays for holding sheets of paper, and particularly, to an input tray capable of automatically aligning the sheets. 
     2. Description of Related Art 
     Scanners and printers may include an input tray for holding a stack of paper sheets. Traditionally, the input tray includes a support plate and two latching members fixedly connected to the support plate for holding the sheets therebetween. A user must align the sheets before putting the sheets into the input tray. This takes time, and is inconvenient to the user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric view of an input tray according to an exemplary embodiment, together with a stack of paper placed thereupon. 
         FIG. 2  is similar to  FIG. 1 , but viewed from the reverse perspective. 
         FIG. 3  is an exploded, isometric view of the input tray of  FIG. 1 . 
         FIG. 4  is similar to  FIG. 3 , but viewed from the reverse perspective. 
         FIG. 5  is a schematic diagram on force analysis and thickness of the paper in the input tray of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are described in detail, with reference to the accompanying drawings. 
     Referring to  FIGS. 1-4 , an input tray  100  for holding a stack of sheets  200  according to an exemplary embodiment is illustrated. The input tray  100  includes a support plate  10 , two latching members  20  slidably connected to the support plate  10 , a cover  30  rotatably connected to the support plate  10 , and a driving mechanism  40  mounted on the support plate  10 . The driving mechanism  40  is used to move the two latching members  20  towards or away from each other. 
     The support plate  10  defines two sliding slots  11  aligned with each other and a sliding hole  12  extending through the plate  10 . The support plate  10  includes a bottom surface  16  facing away the cover  30 . The bottom surface  16  includes a first positioning post  13 , a second positioning post  14  between the two sliding slots  11 , and a stopper block  15  protruding therefrom. 
     Each latching member  20  includes a latching plate  21 , a first rack  22 , and a connecting portion  24  connecting the latching plate  21  and the first rack  22 . The connecting portion  24  extends through one sliding slot  11  of the support plate  10 , allowing the latching member  20  to slide along the grooves  11 . The first rack  22  includes a set of first teeth  23 . 
     The cover  30  includes a base plate  31 , two side plates  32  perpendicular to the base plate  31 , and two protruding blocks  33  (one not shown). The side plates  32  are rotatably coupled to the support plate  10 , allowing the cover  30  to be rotated to a closed position to cover a portion of the support plate  10  or an open position away from the support plate  10 . 
     The driving mechanism  40  includes a detecting assembly  41  rotatably connected to the cover  30 , a slider  42  slidably retained within the sliding hole  12 , an elongated second rack  43  slidably connected to the bottom surface  16  of the support plate  10 , a resilient member  44  applying a pushing force to the second rack  43 , a first gear  45  rotatably sleeved on the first positioning post  13 , an elongated third rack  46  slidably connected to the bottom surface  16 , and a second gear  47  rotatably sleeved on the second positioning post  14 . In the embodiment, the second rack  43  can slide in a direction perpendicular to the sliding direction of the first rack  22 , and the third rack  46  can slide in a direction parallel to the sliding direction of the first rack  22 . 
     The detecting assembly  41  includes a shaft  411 , a cam  412 , and a rocking bar  413  respectively connected to opposite ends of the shaft  411 . The opposite ends of the shaft  411  are rotatably connected to the two protruding blocks  33 . The cam  412  includes a curved surface  4120  with a gradually decreasing radius. The curved surface  4120  abuts firmly against the slider  42 . When the cam  412  is rotated by the shaft  411 , the curved surface  4120  urges the slider  42  to slide along the sliding hole  12 . The rocking bar  413  includes two rotatable rollers  4130  pressing against the sheets  200  under the force of gravity. When the thickness of the stack of sheets  200  decreases, the rotatable rollers  4130  pressing against the sheets move downward, which causes the shaft  411  to rotate. The cam  42  then urges the slider  42  to slide along the sliding hole  12  and away from the support plate  10 . 
     The second rack  43  includes a second inclined surface  430  at one end, and includes a set of second teeth  432  to engage with the first gear  45  at an opposite end thereof. The slider  42  includes a first inclined surface  420  abutting against the first inclined surface  430 . In the embodiment, the resilient member  44  is a coiled spring between the second rack  43  and the stopper block  15 , thereby providing a pushing force to the second rack  43 . The third rack  46  includes two sets of third teeth  460  on two opposite sides and at opposite ends thereof. The two sets of third teeth  460  engage with the first gear  45  and the second gear  47 , and the rotation of the first gear  45  to the second gear  47  is thereby transferred. 
     When putting the sheets  200  into the input tray  100 , the cover  30  is firstly pulled open. The cam  41  disengages from the slider  42 , and the resilient member  44  drives the second rack  43  to move away from the stopper block  15 , urging the slider  42  to move inward to a position in which the slider  42  disengages from the inclined surface  431  of the second rack  43 . The first gear  45  then rotates in a first direction, which causes the third rack  46  to move away from the second rack  43 . The second gear  47  rotates in a reverse direction (second direction), which causes the two latching members  20  to move away from each other. Thus, the width between the latching plates  21  becomes greater than that of the sheets  200 , which facilitates the placing of the sheets  200 . 
     After the sheets  200  are placed on the input tray  100 , the cover  30  is rotated back to the closed position as shown in  FIGS. 1 and 3 . The curved surface  4120  of the cam  412  pushes the slider  42  to move outward, and the second rack  43  is urged to move toward the stopper block  15 . The first gear  45  is urged to rotate in the second direction, which causes the third rack  46  to move toward the second rack  43 . The second gear  47  then rotates in the first direction, which urges the two latching members  20  to move towards each other to a position where the distance between the latching members  20  is slightly less than the width of the sheets  200 . Thus, the sheets  200  can be aligned in a neat stack by the two latching plates  21 , and the two latching plates  21  cooperatively apply a clamping force F to the sheets  200 . 
     When the thickness of the stack of sheets  200  decreases, the rocking bar  413  gradually rotates the shaft  411 . The curved surface  4120  of the cam  412  abutting against the slider  42  gradually moves the slider  42  inwards. The resilient member  44  gradually drives the second rack  43  to move away from the stopper block  15 . The first gear  45  and the third rack  46  gradually drive the second gear  47  to rotate in the second direction, causing the two latching members  20  to move away from each other. Thus, the distance between the two latching members  20  increases, causing the clamping force F to gradually decrease (as shown in  FIG. 5 ) as paper is used and the total thickness of the stack of sheets  200  decreases. 
     While various embodiments have been described and illustrated, the disclosure is not to be construed as being limited thereto. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.