Abstract:
A simplified sheet sensor and registration gate for feeding print media sheets from a stack loaded by a user into a receptacle on a photocopier. The gate is pivoted on the mechanism and has a flag attached; and, upon user loading of sheets into the receptacle, the gate is pivoted against a locking arm and the flag is moved to actuate an optic sensor that sheets have been loaded. The locking arm is pivoted on the nudger roll arm and unlocks the gate when the nudger roll is moved down to contact the top sheet in the stack. When the sheet receptacle is unloaded, the gate is pivoted by gravity to the downward position and the locking arm pivots by gravity to reset. If the nudger is raised for sheet jam clearance, the locking arm is pivoted to clear the gate, allowing the gate to drop. The locking resets by gravity.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to the operation of feeding print media sheets into a photocopier and particularly to such copiers employing a tray or receptacle into which the user loads a stack of sheets to be subsequently automatically fed serially into the photocopier for completion of a desired number of printed copies. In effecting such operations, it is necessary to sense the presence of the print media sheets when loaded in the receptacle by the user and to register the leading edge of the sheets in a stack such that the top sheet of the stack can be correctly positioned for feeding into the copier at a precise location for receiving an image printed thereon. 
         [0002]    Heretofore, the detection of the presence of the print media sheets has been accomplished by optical sensors or interrupt sensors activated by flags or indicators physically moved by the media sheets when loaded into the receptacle or tray. 
         [0003]    Registration of the leading edge of the media sheet stack has heretofore been accomplished by a vertical wall and lift gate provided to guide the sheets over the wall when feeding. One known technique for enabling feeding of the sheets employs a solenoid for activating a plurality of fingers that pivot out of the paper path to permit feeding. In such arrangements, the fingers are pivoted from above the stack and are prevented from rotation until the sheet nudger is lowered onto the stack for feeding. 
         [0004]    This arrangement for sensing, registration and initiating of feeding of sheets from the stack into a photocopier has required the use of costly sensors and mechanisms for registration and feeding of the sheets into the copier. Thus, it has been desired to provide a simplified and less costly construction for a photocopier sheet stack registration and feeding apparatus which provides sufficient locational accuracy for the print media sheets to provide for proper advancement and location of the sheets in the copier to receive an image printed thereon. 
       BRIEF DESCRIPTION 
       [0005]    The apparatus and method of the present disclosure address the above described problem and provide guides on a media sheet tray which are movable for providing lateral sheet registration in the stack to thereby centrally position the sheet stack for subsequent feeding. For feed registration, the user pushes the stack forward such that the leading edge which contacts a registration gate which undergoes a limited movement until making with a stop and subsequently providing a registration surface for the leading edge of the sheets in the stack. The limited movement of the gate between first contact by the leading edge of the sheets in the stack and the gate contacting the stop effects the movement of a flag or indicator away from an optical interrupt sensor which provides a signal to the copier controller that the media sheets are present in the tray or receptacle. Upon receipt of the “sheets present” signal, the machine controller then effects lowering of the nudger into contact with the top sheet in the stack. The lowering of the nudger releases the stop for the registration gate; and, upon activation of the nudger, the movement of the leading edge of the top sheet effects pivoting of the gate upwardly and out of the way to permit feeding of the sheet by the nudger into the copier feeding mechanism. 
         [0006]    When the last sheet in the stack has been fed into the copier, the registration gate returns under the force of gravity to its original position. The nudger is then raised to its upward or original position which effects locking of the gate stop for subsequent loading of media sheets for the next job. 
         [0007]    In the event that there is a paper jam, upon raising of the nudger for clearance, the gate stop is permitted to pivot under the registration gate permitting the gate to return under gravity to its original position; and, the pivoting lock is further rotated under gravitational force to its original position and is, thus, reset. 
         [0008]    The present disclosure describes apparatus and method for economically and simply controlling the sensing and registration of print media sheets in a stack when loaded into the receptacle of a photocopier for commencing a printing job. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an axonometric view of the loading tray or receptacle and feeder for a photocopier; 
           [0010]      FIG. 2  is a perspective view of the feeder mechanism for a photocopier showing the sheet registration gate arm; 
           [0011]      FIG. 3  is a view similar to  FIG. 2  taken from the opposite side with the cover removed to expose the nudger and registration gate locking member; 
           [0012]      FIG. 4  is an end view of the gate and nudger mechanism of  FIG. 3  with the nudger raised and the gate in the downward media sensing position; 
           [0013]      FIG. 5  is a view similar to  FIG. 4  showing the gate in the registered or locked position having sensed the presence of media sheets; 
           [0014]      FIG. 6  is a view similar to  FIG. 5  with the nudger in the downward sheet engaging position; 
           [0015]      FIG. 7  is a view similar to  FIG. 6  with the registration gate released and moved to the upward position during sheet feeding; 
           [0016]      FIG. 8  is a view similar to  FIG. 7  showing the last sheet being fed; 
           [0017]      FIG. 9  is a view similar to  FIG. 8  with the gate and flag returned to the downward original position; 
           [0018]      FIG. 10  is a view similar to  FIG. 7  showing media sheet jammed in the feeder; 
           [0019]      FIG. 11  is a view similar to  FIG. 10  with the nudger in the raised position for jam clearance; 
           [0020]      FIG. 12  is a view showing the jam cleared and the gate in the fully downward position with the flag and the sensor ready for reloading; 
           [0021]      FIG. 13  is a view similar to  FIG. 12  showing the pivoting lock lowered under the force of gravity to the locking position; and 
           [0022]      FIG. 14  is an enlarged view showing the arrangement of the gate and locking mechanism showing that the forces act through the pivot center of the nudger. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Referring to  FIG. 1 , a feeder mechanism for a copier indicated generally at  10  includes a receptacle indicated generally at  12  having a support platform or tray  14  with a pair of spaced generally parallel guides  16 ,  18  provided thereon which are laterally moveable on the tray. Each of the guides  16 ,  18  has a portion thereof (not shown) extending downwardly therefrom into a pair of laterally extending guide slots  20 ,  22  formed in the tray  14 . The guides may be moved toward the center of the tray for registering and aligning the lateral edges of the print media sheets placed in the tray at the time of loading. 
         [0024]    Referring to  FIGS. 2 and 3 , a feeder mechanism is illustrated as having a registration gate or arm  24  pivotally mounted about a pin  26  providing a nudger arm  28  which is pivoted about the axis of a feeder roll  30 . The gate extends downwardly through a slot  17  formed in the feeder pan  15 . 
         [0025]    The nudger arm  28  has attached thereto an axle about which is pivoted a nudger roll  32  which is driven by a gear  34  engaged by idler gear  36  which is driven by gear  38  on the feeder roll  30 . The feeder roll is powered separately by a motor controlled by the electronic controller (not shown) for the copier. Referring to  FIG. 4 , the gate  24  has a flag  40  attached thereto for pivotal movement about stationary pin  26  which is shown in  FIG. 4  in the position interrupting a beam in a photodetector  42  disposed for detecting the position of flag  40  and, thus, gate  24 . 
         [0026]    The gate  24  is shown in  FIG. 4  in its fully downward position with the gate arm in the media detecting position; and, the nudger arm  28  is shown in its upward position with the nudger roller  32  away from the tray  14 . 
         [0027]    A locking arm  44  is pivotally mounted about pin  46  on the nudger arm  28 ; and, the arm  44  has a finger portion  48  disposed on one side of the pivot for engagement by the gate arm locking portion  50 . The end of the arm  44  opposite the locking portion  48  has a notch  52  provided thereon which contacts a stop pin  54  provided on the nudger arm. 
         [0028]    With the gate  24  in the fully downward position shown in  FIG. 4  and flag  40  engaging the sensor  42 , the locking portion or surface  50  of the gate  24  is spaced from the end of the portion  48  of locking arm  44  by a limited amount. The locking arm  44  is pivoted under the force of gravity about pin  46  such that notch  52  contacts stop pin  54 . The mechanism is shown in  FIG. 4  in the position ready to receive loading of sheets of print media into tray  14  by the user pushing the sheets into contact with arm  24  as indicated by the black arrow and the designation “Media”. 
         [0029]    Referring to  FIG. 5 , the gate  24  is shown as having been moved by the media sheets indicated by the black arrow and a designation “Media” to a position where the locking surface  50  has engaged the end of the locking arm portion  48  of the locking arm  44  such that the gate  24  is locked, in the position shown in  FIG. 5 , and thus acts as a registration surface for the leading edge of the stack of media sheets. The flag  40  has been raised from the sensor  42  which movement sends a signal from sensor  42  to the controller that the media sheets have been loaded into the tray  14 . The nudger arm  28  remains in the upward position with the nudger roll  32  spaced away from the media sheets in the tray  14 . 
         [0030]    Referring to  FIG. 6 , the nudger arm  28  is shown as having been lowered to a position such that the nudger roll  32  engages the top sheet in the stack loaded into the tray  14  as denoted by the black arrow labeled “Media” in  FIG. 6 . The gate  24  has been unlocked by virtue of the end  48  of the locking arm  44  having pivoted downward with the nudger arm  28  to free the contact surface  50  on the gate arm. Thus, in the position shown in  FIG. 6 , the mechanism is ready for sheets to be fed by the nudger roller  32  into the feed rollers  30 ,  31  along the tray  14 . 
         [0031]    Referring to  FIG. 7 , the nudger roll  32  has been powered as are the feed rollers  31 ,  32 ; and, the top sheet of print media is being fed from the stack on the guide pan  15  as indicated by the black arrow and the designation “Media” through the feed rolls  31 ,  32 . The leading edge of the media sheet has caused the gate  24  to be moved to the upward position as shown in  FIG. 7  clearing the path for the sheets to be fed into the feed rolls  31 ,  32 . 
         [0032]    Referring to  FIG. 8 , the last of the media sheets in the stack loaded into tray  14  is shown as passing through the feeder rolls  30 ,  31  by the black arrow labeled “Media”; and, the gate is shown in its upward position with the nudger roll still in the lowered or driving position. 
         [0033]    Referring to  FIG. 9 , upon completion of the print job and unloading of the tray  14  the nudger arm  28  has been raised; and, the passage of the last print media sheet has permitted the gate  24  to drop under the force of gravity to its original position with the flag  40  interrupting the photo beam of sensor  42 . The raising of the nudger arm  28  causes the arm  44  to be raised and the locking end portion  48  to remain clear of the contact surface  50  on the gate  24 . Thus, the gate  24  is in position to again receive sheets in the tray  14  with a leading edge contacting gate  24  for limited movement in response thereto. The entry of flag  40  into sensor  42  thus signals the controller that the mechanism is in a condition to again receive sheets loaded by the user into tray  14 . 
         [0034]    Referring to  FIG. 10 , the mechanism is shown with the nudger arm dropped into a position for feeding media sheets to feed rollers  30 ,  31  with gate  24  moved to its forward position by a media sheet feeding through the roller  30 ,  31 ; however, the media sheet is shown as in a “jammed” or misfed condition wherein the machine has stopped the power to the feed rollers  30 ,  31  and the nudger roller  32 . 
         [0035]    Referring to  FIG. 11 , the mechanism is shown in the condition of  FIG. 10  with a print media sheet jammed between rollers  30 ,  31 ; however, in the condition in  FIG. 11 , the nudger arm  28  has been raised to move the nudger roller  32  upward and away from the guide pan  15 . The upward movement of the nudger arm  28  has caused the locking arm  44  to be raised by the movement of the pivot pin  46  with the nudger arm  28 . This movement causes portion  48  of the locking arm  44  to slide along surface  56  under the locking surface  50  of the gate  24 . Thus, the gate  24  is not locked in the upward position but is maintained there by the friction of the media sheet acting on the lower edge of the gate  24 . 
         [0036]    Referring to  FIG. 12 , the situation of a jammed media sheet shown in  FIG. 11  has been relieved by removal of the jammed sheet; and, the gate  24  is thus allowed to drop under the force of gravity pivoting about the pivot pin  26  and returns to its downward initial position shown in  FIG. 12  with the flag  40  again interrupting the beam in the photo optic sensor  42 . The nudger arm  28  remains in the upward position away from the feeder pan  15 ; and, the mechanism is ready to be reset for continuing the job. 
         [0037]    Referring to  FIG. 13 , the state of the mechanism shown in  FIG. 12  is further prepared for continuation of the printing job by the rotation of the locking arm  44  about the pin  46  under the force of gravity until the notch  52  in the arm  44  again rests on the locking arm stop pin  54  as shown in  FIG. 13 . In the position shown in  FIG. 13 , the locking arm  44  has its end portion  48  again positioned adjacent the gate locking surface  50  and slightly spaced therefrom to permit registration of the media sheets in the stack against the gate  24  which will cause the gate to move to the vertically downward position (see  FIG. 5 ) whereupon surface  50  will contact the end  48  of the locking arm  44  and secure the gate from further movement. 
         [0038]    Referring to  FIG. 14 , the gate  24  is shown in the media sheet stack registration position with the locking surface  50  contacting end  48  of the gate locking  44 . The angle of this locking surface  50  ensures that the nudger may be dropped completely un-hindered by the force of gate  24  and ‘locked out’ against locking arm  44 . Feeding of media sheets can then resume. The black arrows indicate the line of the reaction force from the sheet stack against the gate, illustrating that the force is biased to the correct side of pin  46  ensuring that the rotation of the locking arm  44  is in the correct direction (clockwise as depicted in this view) to enable the locking arm  44  to be ‘locked out’ shown by the surface of notch  52  in contact with stop pin  54 . The sequence of events and mechanism state is shown in Table I. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                   
                   
                   
                   
                 PIVOTING 
               
               
                 PAPER 
                 NUDGER 
                 GATE 
                 FLAG 
                 LOCK 
               
               
                   
               
             
             
               
                 PRESENTED 
                 UP (AWAY) 
                 DOWN 
                 IN 
                 OPEN 
               
               
                 REGISTERED 
                 UP 
                 REGISTER 
                 OUT 
                 ENGAGED 
               
               
                 AGAINST 
                   
                 POSITION: 
               
               
                 GATE 
                   
                 LOCKED 
               
               
                 REGISTERED 
                 DOWN 
                 REGISTER 
                 OUT 
                 OPEN 
               
               
                   
                   
                 POSITION 
               
               
                   
                   
                 (UN- 
               
               
                   
                   
                 LOCKED) 
               
               
                 FED BY 
                 DOWN AND 
                 UP 
                 OUT 
                 OPEN 
               
               
                 NUDGER 
                 POWERED 
               
               
                 LAST 
                 DOWN 
                 DOWN 
                 IN 
                 OPEN 
               
               
                 SHEET FED 
               
               
                 JOB 
                 UP 
                 DOWN 
                 IN 
                 RESET 
               
               
                 COMPLETED 
                   
                   
                   
                 OPEN 
               
               
                 JAMMED 
                 DOWN 
                 UP 
                 OUT 
                 OPEN 
               
               
                 JAM 
                 UP 
                 FALLS 
                 IN 
                 OPEN RESET 
               
               
                 CLEARED 
                   
                 DOWN: 
               
               
                   
                   
                 RESET 
               
               
                 REGISTERED 
                 UP 
                 REGISTER 
                 OUT 
                 ENGAGED 
               
               
                 AGAINST 
                   
                 POSITION 
               
               
                 GATE 
                   
                 (LOCKED) 
               
               
                 REGISTERED 
                 DOWN 
                 REGISTER 
                 OUT 
                 OPEN 
               
               
                   
                   
                 POSITION 
               
               
                   
                   
                 (UN- 
               
               
                   
                   
                 LOCKED) 
               
               
                   
               
             
          
         
       
     
         [0039]    The method and apparatus of the present disclosure thus provides a media sheet stack registration and feeding operation with a reduced number of parts for the mechanism and combines in the gate the function of sensing the presence of the print media sheets in the stack by the leading edge thereof and the registration of the stack. The gate moves from an initial position to a locked position; and, upon lowering of the nudger arm for powering the nudger roll, the gate lock is released and feeding of the sheets effects movement of the gate to an upward position permitting advancing of the sheets to the feeder rolls. In the event of a paper jam, raising of the nudger roll permits the gate lock to move to a reset position under the force of gravity and the gate itself returns to a closed position under the force of gravity. Upon re-lowering of the nudger arm for continuing the print job, the gate locking mechanism is effective upon the gate sensing the presence of print media sheets in the stack. 
         [0040]    It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.