Patent Publication Number: US-11046547-B2

Title: Bail control for sheet media

Description:
BACKGROUND 
     The output devices used in or with some printers, copiers, and other sheet media processing machines include a bail to help control sheets discharged to a stack of sheets. The sheets slide under the bail as they are discharged on to the stack, for example to stop each sheet in the desired position in the output tray. 
    
    
     
       DRAWINGS 
         FIG. 1  is a block diagram illustrating an example bail system for a sheet media tray. 
         FIGS. 2 and 3  are isometric views illustrating an example for implementing a bail system such as the one shown in the block diagram of  FIG. 1 . 
         FIGS. 4-13  are isometric views illustrating another example for implementing a bail system such as the one shown in the block diagram of  FIG. 1 . 
         FIG. 14  is an isometric view illustrating another example for implementing a bail system such as the one shown in the block diagram of  FIG. 1 . 
         FIG. 15  is a block diagram illustrating another example of a bail system for a sheet media tray. 
     
    
    
     The same part numbers designate the same or similar parts throughout the figures. The figures are not necessarily to scale. 
     DESCRIPTION 
     Some sheet media processing machines are capable of processing multiple different sheet types and sizes. The speed, force, or other sheet discharge conditions may vary in a particular machine or between different machines that utilize the same type of output device. For example, the bail force desired to properly control a sheet of uncoated A3 size printer paper may be inadequate to properly control a shorter stiffer A4 sheet of paper or a slicker sheet of coated paper. 
     A new bail system has been developed to help expand the range of forces a bail can deliver to accommodate a greater variety of media sheets and discharge conditions. In one example, a bail system includes a bail to apply a force to the sheets, a spring or other bias mechanism to counter the force of the bail on the sheets, and a control mechanism to control the degree to which the bias mechanism counters the force of the bail on the sheet. The control mechanism may be implemented, for example, using a lost motion coupler between the bail axle and the bail and between the axle and a motor drive train, to control the torque applied to the bail axle by the bias spring. The control mechanism may be implemented, for another example, using an actuator to vary the tension in the bias spring, to control the torque applied to the bail axle by the spring. 
     These and other examples shown in the figures and described below illustrate but do not limit the scope of the patent, which is defined in the Claims following this Description. 
     As used in this document: “and/or” means one or more of the connected things; a “bail” means a hinged arm to hold or position media sheets in a tray; a “bias mechanism” means a mechanism to urge something toward a position or state; a “lost motion coupler” means a coupler in which a gap between the parts creates a range of motion through which a part may be moved without applying force or motion to another part; a “processor readable medium” means any non-transitory tangible medium that can embody, contain, store, or maintain instructions for use by a processor and may include, for example, circuits, integrated circuits, ASICs (application specific integrated circuits), hard drives, random access memory (RAM), read-only memory (ROM), and memory cards and sticks and other portable storage devices; and a “tray” means a structure to support media sheets including, for example, an input tray or an output bin. 
       FIG. 1  is a block diagram illustrating one example of a bail system  10  for a sheet media tray  12 . Referring to  FIG. 1 , bail system  10  includes a bail  14  to apply a force to a sheet  16  in tray  12 . Tray  12  in  FIG. 1  represents any suitable structure to hold or otherwise support individual media sheets or a stack of media sheets including, for example, the bins in an output device used with (or on) a printer or copier. Bail system  10  also includes a bias mechanism  18  to counter the force applied by bail  14  on a sheet  16  in tray  12  and a control mechanism  20  to control the degree to which bias mechanism  18  counters the force of bail  14  on sheet  16 . 
       FIGS. 2 and 3  illustrate one example for implementing a bail system  10  such as the one shown in the block diagram of  FIG. 1 . Referring to  FIGS. 2 and 3 , bias mechanism  18  is implemented as a spring  19  and control mechanism  20  is implemented as an actuator  21  to adjust the tension in spring  19 . Bail  14  is positioned over tray  12  to apply a bail force to a sheet or stack of sheets in tray  12 . An upstream part  24  of bail  14  is supported on an axle  22  and a downstream part  26  of bail  14  extends out over tray  12 . Thus, in the absence of a counter force applied by bias spring  19 , downstream end  26  of bail  14  rests on tray  12  (or sheets in tray  12 ) and the bail force applied to a sheet moved into tray  12  corresponds directly to the weight of the bail. Other suitable bail force configurations are possible. For example, bail  14  may be spring loaded against tray  12  to increase the bail force. “Upstream” and “downstream” in this context refer to the direction sheets are moved into tray  12 . 
     Counter force bias spring  19  is connected to axle  22  through a lever arm  28  to exert a biasing torque on the axle, as indicated by arrow  30  in  FIG. 3 . In this view, the direction of torque  30  is clockwise. The magnitude of torque  30  is determined by the force of spring  19  and the effective length of lever arm  28 . In this example, the counter force generated by torque  30  is transmitted to bail  14  through a pin  32  on axle  14  in a hole  34  in bail  14 . The pin/hole transmission shown in  FIGS. 2 and 3  is just one example. Other suitable transmissions are possible. 
     Also in this example, bias spring  19  is configured as an extension spring connected between a chassis or other stationary part  36  and lever arm  28 . A linear actuator  21  controls the length of spring  19  to adjust the counter force applied to bail  14 . Actuator  21  may be operated manually, or actuator  21  may be operated automatically using a motor and programmable controller. Although a rack and pinion actuator  21  is shown, any suitable linear actuator may be used to adjust the length of an extension spring  20 . Other suitable spring/actuator configurations are possible. For example, a torsion spring connected to axle  22  could be used in combination with a rotary actuator, to apply the desired counter force to bail  14 . 
     In one example, spring  19 , actuator  21 , and lever arm  28  are configured together to achieve a range of counter forces between 0 and something exceeding the weight of bail  14 . When actuator  21  is set to apply 0 counter force, then the bail force is unaffected by spring  19 . When actuator  21  is set to apply a counter force greater than 0 but less than the weight of bail  14 , then bail  14  will continue to rest on tray  12  (or sheets in tray  12 ) with a bail force less than the weight of bail  14 . When actuator  21  is set to apply a counter force greater than the weight of bail  14 , then bail  14  will be lifted off tray  12  to further reduce or eliminate the bail force applied to sheets moved into tray  12 . 
       FIGS. 4-13  illustrate another example for implementing a bail system  10 .  FIG. 4  shows bail system  10  with a tray  12  and chassis  36 .  FIGS. 5-7, 8-10 , and  11 - 13  are detail views with each set of figures showing a different position for components in the bail system. Referring to  FIGS. 4-13 , control mechanism  20  includes a motor  38  operatively connected to axle  22  through a drive train  40  and a first lost motion coupler  42 . Control mechanism  20  may also include a position encoder  43  operatively connected to motor  38  to help accurately locate the parts. In this example, as best seen in  FIGS. 6, 9, and 12 , lost motion coupler  42  includes a driving finger  44  at the end of drive train  40  and a mating, driven fitting  46  at the end of axle  22 . Drive finger  44  engages axle fitting  46  at each end  48 ,  50  of a gap  52 . Gap  52  creates a range of motion through which finger  44  may be moved without applying force or motion to fitting  46  and thus axle  22 . In the examples shown in the figures, drive finger  44  is configured as a V-shaped part to help mate effectively with each end  48 ,  50  on fitting  46  and to increase strength within the molding constraints for a plastic part  46 . 
     Control mechanism  20  also includes a second lost motion coupler  54  to couple axle  22  to bail  14 . In this example, lost motion coupler  54  includes pin  32  on axle  22  and a slot  34  in bail  14 . Pin  32  can engage bail  14  at each end of slot  34 . Slot  34  forms a gap that creates a range of motion through which one or both of pin  32  and bail  14  may be moved without applying force or motion to the other part, for example to allow bail  14  to be lifted as media sheets are added to tray  12 . 
     The direction of torque  30  ( FIG. 8 ) from bias spring  19  is counterclockwise when viewed from the perspective shown in  FIGS. 5-13 . Thus, when motor  38  rotates driving finger  44  away from gap end  48  counterclockwise into gap  52 , then axle  22  can rotate counterclockwise at the urging of spring  19  to move axle pin  22  toward the countering (lifting) end of bail slot  24 , as best seen by comparing the position of the parts in  FIGS. 5-7 and 8-11 . As shown in  FIGS. 8-11 , bias spring  19  has rotated axle pin  32  to the countering end of slot  34  to engage bail  14 , and thus couple spring  19  to bail  14  to apply the desired counter force to bail  14 . Correspondingly, spring  19  has rotated gap end  48  toward drive finger  44 . When the counter force applied by spring  19  is greater than the bail force, so that spring lifts bail  14 , then spring  19  will rotate axle  22  until gap end  48  contacts drive finger  44 . Thus, the position of drive finger  44  may be used as a stop to limit the extent of lift. 
     When motor  38  rotates drive finger  44  clockwise against gap end  48  to override spring  19 , then axle  22  rotates clockwise to move axle pin  32  away from the countering end of bail slot  34 , to decouple bail  14  from bias spring  19  (no counter force applied to bail  14 ), as shown in  FIGS. 5-7 . Motor  38  may be rotated counterclockwise against gap end  50  to lift bail  14 , as shown in  FIGS. 11-13 . While gap  52  (with ends  48 ,  50 ) is on the axle side of coupler  42  in this example, gap  52  could be on the motor side of coupler  42 . 
     The use of two lost motion couplers  42 ,  54  enables the selective application of a counter force to bail  14  while still allowing bail  14  to function free of any force from either spring  19  or motor  38 . For example, without a lost motion coupler  54  to couple axle  22  to bail  14 , motor  38  could not override spring  19  without also depressing bail  14 , and without a lost motion coupler  42  to couple motor  38  to axle  22 , motor  38  would always override spring  19  (by always applying a torque to axle  22 ) thus rendering spring  19  ineffective to counter the bail force. 
       FIG. 14  illustrates another example for implementing a bail system  10 . Referring to  FIG. 14 , control mechanism  20  includes an actuator  21  and a motor  38 , drive train  40  and lost motion couplers  42 ,  54 . Thus, in this implementation for bail system  10 , the magnitude of the counter force applied to bail  14  from bias spring  19  may be adjusted with actuator  21  along a continuum, as described above with reference to  FIGS. 2 and 3 , and the counter force may be turned on and off with motor  38 , as described above with reference to  FIGS. 4-13 . 
     As shown in  FIG. 15 , bail system  10  may also include a controller  56  to control elements of mechanism  20 . The parts referenced in the following description that do not appear in  FIG. 15  are shown in  FIGS. 2-14 . Referring to  FIG. 15 , controller  56  includes torque control instructions  58  to selectively torque a bail axle  22  to vary the bail force applied to sheets in a media tray. Instructions  58  reside on a processor readable medium  60  and are executed by a processor  62  on controller  56 . Controller  56  may be implemented, for example, in a controller for the printer, copier or other sheet processing machine or in a “local” controller for actuator  21  and/or motor  38  in a control mechanism  20 . In one example, instructions  58  include instructions to selectively torque axle  22  to vary the bail force by varying the tension in a bias spring  19 , as described above with reference to  FIGS. 2 and 3 . In one example, instructions  58  include instructions to selectively torque axle  22  to vary the bail force by coupling a bias mechanism  18  to bail  14  to counter the force of bail  14  and decoupling the bias mechanism  18  from bail  14  to not counter the force of bail  14 , as described above with reference to  FIGS. 4-13 . 
     As noted above, the examples shown in the figures and described herein illustrate but do not limit the patent, which is defined in the following Claims. 
     “A”, “an” and “the” used in the claims means one or more. For example, “a bias mechanism” means one or more bias mechanisms and “the bias mechanism” means the one or more bias mechanisms.