Patent Publication Number: US-7896340-B2

Title: Print media registration system and method

Description:
BACKGROUND 
     In a printing system for printing on print media, it is desirable for the print media to be aligned as accurately as possible to register the print media for feeding through the printing system. Deviations from aligned or straight feeding of the print media can result in image skew. More specifically, misalignment of the print media can result in an image that is printed on the print media as being tilted or angled relative to the print media. Accordingly, registering the print media to align or deskew the print media before printing of the image on the print media is desirable. 
     For these and other reasons, a need exists for the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional view illustrating one embodiment of a portion of a printing system including one embodiment of a print media registration system. 
         FIG. 2  is a schematic cross-sectional view illustrating one embodiment of operation of the print media registration system of  FIG. 1 . 
         FIG. 3  is a schematic cross-sectional view illustrating one embodiment of further operation of the print media registration system of  FIG. 2 . 
         FIG. 4  is a schematic cross-sectional view illustrating another embodiment of operation of the print media registration system of  FIG. 1 . 
         FIG. 5  is a schematic cross-sectional view illustrating one embodiment of further operation of the print media registration system of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. 
       FIG. 1  schematically illustrates one embodiment of a portion of a printing system  10 . Printing system  10  is defined to include any device or system capable of producing or generating printed output such as, for example, an ink jet printer, a laser printer, a thermal transfer printer, or a multi-functional device providing printing, copying, and/or scanning capabilities. 
     In one embodiment, printing system  10  includes a media tray  20 , a pick assembly  30 , a registration assembly  40 , and a controller  50 . As described below, media tray  20 , pick assembly  30 , and registration assembly  40  are arranged and configured to supply print media  12  to a media path  14  of printing system  10  for printing on print media  12 . More specifically, media tray  20  holds print media  12  and pick assembly  30  picks a sheet of print media  12  and routes print media  12  to media path  14 . Registration assembly  40  is positioned in media path  14  after pick assembly  30  and senses print media  12  in media path  14 . As such, registration assembly  40  registers print media  12  in media path  14 , and then advances print media  12  along media path  14 , as described below. 
     In one embodiment, media tray  20  supports or holds a plurality of sheets of print media  12  in a stacked arrangement or configuration. The stacked arrangement or configuration of print media  12  results in a stack height of print media  12 . Accordingly, the stack height of print media  12  varies based on a quantity or amount of print media  12  held by media tray  20 . In one exemplary embodiment, media tray  20  holds between 1 and 100 sheets of print media  12 . 
     In one embodiment, media tray  20  includes a backing plate  22  and a transition plate  24 . Backing plate  22  and transition plate  24  are arranged such that backing plate  22  supports a surface of print media  12  and transition plate  24  supports an edge of print media  12 . In one exemplary embodiment, transition plate  24  extends from backing plate  22  in a horizontal manner and guides print media  12  to media path  14 . 
     In one embodiment, backing plate  22  is oriented at an angle to horizontal. In one exemplary embodiment, the angle of backing plate  22  is an obtuse angle. As such, in the exemplary embodiment, print media  12  supported by media tray  20  is oriented in a vertical manner at an angle corresponding to the angle of backing plate  22 . 
     In one embodiment, pick assembly  30  includes a pick arm  32  and a pick roller  34 . Pick roller  34  is supported by pick arm  32  and contacts a top sheet  121  of the stack of print media  12  to pick top sheet  121  of print media  12  from the stack. In one embodiment, pick arm  32  is an articulating arm and is biased toward backing plate  22  of media tray  20  such that pick arm  32  moves toward backing plate  22  as print media  12  is removed from media tray  20 . 
     In one embodiment, pick assembly  30  also includes a spacer wheel  36 . Spacer wheel  36  is supported by pick arm  32  and maintains contact with a top sheet of the stack of print media  12  as print media  12  is removed from media tray  20 . As such, spacer wheel  36  and, therefore, pick arm  32  follow the stack height of print media  12 . Thus, in one embodiment, a stack height and/or a quantity or amount of print media  12  held in or supported by media tray  20  is determined from the position of pick arm  32 . Although only one pick roller  34  and one spacer wheel  36  are illustrated and described, it is within the scope of the present invention for pick assembly  30  to include one or more pick rollers  34  and/or one or more spacer wheels  36 . 
     In another embodiment, printing system  10  includes a media tray sensor  26 . Media tray sensor  26  senses print media  12  in media tray  20  and provides feedback and/or input regarding a stack height and/or a quantity or amount of print media  12  held in or supported by media tray  20 . In one embodiment, media tray sensor  26  includes a low media sensor of printing system  10 . 
     In one embodiment, the position of pick arm  32  and/or input from media tray sensor  26  is used to determine a stack height and/or a quantity or amount of print media  12  held in or supported by media tray  20 . As such, the stack height and/or quantity or amount of print media  12  held in or supported by media tray  20  is used to control operation of registration assembly  40 , as described below. 
     In one embodiment, registration assembly  40  includes a feed roller  42  and a pinch roller  44 . Pinch roller  44  is positioned opposite feed roller  42  such that feed roller  42  and pinch roller  44  form a nip  46  therebetween. As described below, pick assembly  30  routes print media  12  to nip  46  such that registration assembly  40  registers print media  12  in media path  14 . Thereafter, registration assembly  40  advances print media  12  along media path  14 . Although only one feed roller  42  and one pinch roller  44  are illustrated and described, it is within the scope of the present invention for registration assembly  40  to include one or more feed rollers  42  and/or one or more pinch rollers  44 . 
     In one embodiment, registration assembly  40  also includes a media path sensor  48 . Media path sensor  48  senses print media  12  in media path  14  and provides feedback or input for operating registration assembly  40  and, more specifically, feed roller  42  of registration assembly  40 , as described below. 
     In one embodiment, controller  50  communicates with pick assembly  30  and registration assembly  40  to control operation of pick assembly  30  and registration assembly  40 , as described below. More specifically, in one embodiment, controller  50  communicates with pick arm  32  and pick roller  34  of pick assembly  30 , and communicates with feed roller  42  and media path sensor  48  of registration assembly  40 . As such, controller  50  receives feedback or input from pick arm  32  regarding a position of pick arm  32 , and provides output to pick roller  34  for operation of pick roller  34  and picking of print media  12  from media tray  20 . In addition, controller  50  receives feedback or input from media path sensor  48  regarding a position of print media  12  in media path  14 , and provides output to feed roller  42  for operation of feed roller  42  and registering of print media  12  in media path  14 . 
     In one embodiment, with input of the position of pick arm  32  or input from media tray sensor  26 , controller  50  determines a stack height and/or a quantity or amount of print media  12  held in or supported by media tray  20 . In addition, with input of media path sensor  48 , controller  50  determines a position of print media  12  in media path  14 . As such, based on the stack height and/or quantity or amount of print media  12  held in or supported by media tray  20  and the position of print media  12  in media path  14 , controller  50  provides output to feed roller  42  for registering print media  12  in media path  14 , as described below. 
       FIGS. 2 and 3  illustrate one embodiment of operation of printing system  10  including, more specifically, picking, registering, and feeding of print media  12  in printing system  10 . As illustrated in the embodiment of  FIG. 2 , pick roller  34  of pick assembly  30  is operated to pick top sheet  121  of print media  12  from media tray  20  and route top sheet  121  to media path  14  and nip  46  between feed roller  42  and pinch roller  44  of registration assembly  40 . In the illustrated embodiment, pick roller  34  is rotated counterclockwise to pick top sheet  121  of print media  12  and route top sheet  121  to media path  14  and nip  46 . As such, top sheet  121  of print media  12  is routed to nip  46  in a first direction. 
     In one embodiment, after media path sensor  48  senses a leading edge  121   a  of top sheet  121  in media path  14 , feed roller  42  of registration assembly  40  is operated to register top sheet  121  in media path  14 . More specifically, in the illustrated embodiment, feed roller  42  is rotated counterclockwise in a second direction opposite the first direction. As such, nip  46  between feed roller  42  and pinch roller  44  is driven opposite to the direction in which top sheet  121  is fed to nip  46 . Thus, feed roller  42  and pinch roller  44  register top sheet  121  in media path  14 . In registering top sheet  121  in media path  14 , feed roller  42  and pinch roller  44  deskew or align top sheet  121  in media path  14 . 
     In one embodiment, registration assembly  40  is operated for a predetermined time based on the quantity or amount of print media  12  in media tray  20  to register print media  12  in media path  14 . More specifically, as the quantity or amount of print media  12  in media tray  20  decreases, the predetermined time that registration assembly  40  is operated to register print media  12  in media path  14  increases, as described below. 
     As illustrated in the embodiment of  FIG. 3 , after registration assembly  40  has been operated for the predetermined time to register print media  12  in media path  14 , pick assembly  30  is released and registration assembly  40  is operated to advance top sheet  121  of print media  12  along media path  14 . More specifically, in the illustrated embodiment, pick roller  34  is idled and feed roller  42  is rotated clockwise. As such, nip  46  between feed roller  42  and pinch roller  44  is driven in the first direction. Thus, feed roller  42  and pinch roller  44  advance top sheet  121  along media path  14  in the first direction. 
       FIGS. 4 and 5  illustrate another embodiment of operation of printing system  10 , including, more specifically, picking, registering, and feeding of print media  12  in printing system  10 . As illustrated in the embodiment of  FIGS. 4 and 5 , the stack height and/or the quantity or amount of print media  12  in media tray  20  is less than that of the embodiment of  FIGS. 2 and 3 . For example, in one exemplary embodiment,  FIGS. 2 and 3  include a stack height of approximately 100 sheets of print media  12  whereas  FIGS. 4 and 5  illustrate a stack height of approximately 10 sheets of print media  12 . 
     As illustrated in the embodiment of  FIG. 4 , pick roller  34  of pick assembly  30  is operated to pick a top sheet  122  of print media  12  from media tray  20  and route top sheet  122  to media path  14  and nip  46  between feed roller  42  and pinch roller  44  of registration assembly  40 . In the illustrated embodiment, pick roller  34  is rotated counterclockwise to pick top sheet  122  of print media  12  and route top sheet  122  to media path  14  and nip  46 . As such, top sheet  122  of print media  12  is routed to nip  46  in a first direction. 
     In one embodiment, after media path sensor  48  senses a leading edge  122   a  of top sheet  122  in media path  14 , feed roller  42  of registration assembly  40  is operated to register top sheet  122  in media path  14 . More specifically, in the illustrated embodiment, feed roller  42  is rotated counterclockwise in a second direction opposite the first direction. As such, nip  46  between feed roller  42  and pinch roller  44  is driven opposite to the direction in which top sheet  122  is fed to nip  46 . Thus, feed roller  42  and pinch roller  44  register top sheet  122  in media path  14 . In registering top sheet  122  in media path  14 , feed roller  42  and pinch roller  44  deskew or align top sheet  122  in media path  14 . 
     As described above, registration assembly  40  is operated for a predetermined time based on the quantity or amount of print media  12  in media tray  20  to register print media  12  in media path  14 . More specifically, as the quantity or amount of print media  12  in media tray  20  decreases, the predetermined time that registration assembly  40  is operated to register print media  12  in media path  14  increases, as described below. 
     In one embodiment, as described above, pick arm  32  is an articulating arm and is biased toward backing plate  22  of media tray  20  such that spacer wheel  36  maintains contact with a top sheet of print media  12 . As such, with a reduced stack height of print media  12 , pick arm  32  moves closer to backing plate  22 . Thus, compared to the higher stack height of print media  12  in the embodiment of  FIG. 2 , a distance of media path  14  from pick roller  34  to feed roller  42  is greater with the lower stack height of print media  12  in the embodiment of  FIG. 4 . 
     Accordingly, with the lower stack height of print media  12  in the embodiment of  FIG. 4 , a longer uncontrolled length of top sheet  122  of print media  12  exists. As a result, a degree or amount of skew or misalignment of top sheet  122  maybe greater in the embodiment of  FIG. 4  than a degree or amount of skew or misalignment of top sheet  121  in the embodiment of  FIG. 2 . Thus, the predetermined time that registration assembly  40  is operated to register top sheet  122  of print media  12  in media path  14  in the embodiment of  FIG. 4  is greater than the predetermined time that registration assembly  40  is operated to register top sheet  121  of print media  12  in media path  14  in the embodiment of  FIG. 2 . 
     As illustrated in the embodiment of  FIG. 5 , after registration assembly  40  has been operated for the predetermined time to register print media  12  in media path  14 , pick assembly  30  is released and registration assembly  40  is operated to advance top sheet  122  of print media  12  along media path  14 . More specifically, in the illustrated embodiment, pick roller  34  is idled and feed roller  42  is rotated clockwise. As such, nip  46  between feed roller  42  and pinch roller  44  is driven in the first direction. Thus, feed roller  42  and pinch roller  44  advance top sheet  122  along media path  14  in the first direction. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.