Feeding sheets into a photocopier

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.

1 . A sheet feeding mechanism for a photocopier comprising:
 (a) a sheet stack receptacle for user loading a supply of print media with guides for directing sheet feed;   (b) a registration gate disposed to be contacted by the leading edge of the sheets to be fed and movable between an open and closed position, the gate moveably responsive upon the sheets contacting the gate to effect a sheet position signal;   (c) a sensor operable to detect the sheet position signal and provide an output signal;   (d) a releasable stop operable to maintain the gate in a closed position upon contact thereby; and,   (e) a sheet nudger moveable between a first position contacting a sheet from a stack to be fed and a second position away from the stack, wherein movement of the nudger to the first position effects release of the stop thereby allowing a sheet, upon urging of the nudger, to effect opening of the gate and upon energization of the nudger permitting sheet movement for feeding into the copier.   
     
     
         2 . The mechanism defined in  claim 1 , wherein the gate is mounted on the mechanism for pivotal movement. 
     
     
         3 . The mechanism defined in  claim 1 , wherein the gate includes a flag moveable therewith for effecting the signal. 
     
     
         4 . The mechanism defined in  claim 1 , wherein the sensor includes an electro-optic device; 
     
     
         5 . The mechanism defined in  claim 1 , wherein upon completion of sheet feeding from the stack, the gate is moved from the open position under the force of gravity to the closed position. 
     
     
         6 . A method of loading print media sheets from a receptacle into a feeder mechanism comprising:
 (a) disposing a moveable gate between the sheets and the feeder mechanism, and releasably locking the gate in a closed sheet registering position;   (b) sensing movement of the gate and generating a control signal;   (c) moving a nudger into a sheet contacting position in response to the control signal and relieving the gate lock; and,   (d) energizing the nudger and moving a sheet for effecting movement of the gate to an open position.   
     
     
         7 . The method defined in  claim 6 , further comprising, when the receptacle is unloaded, moving the nudger to an away position and permitting the gate to close under the force of gravity. 
     
     
         8 . The method of  claim 6 , wherein the step of sensing movement of the gate includes disposing a flag with the gate and sensing movement of the flag. 
     
     
         9 . The method defined in  claim 6 , wherein the step of sensing movement of the gate includes electro-optically sensing movement of a flag on the gate. 
     
     
         10 . The method defined in  claim 6 , wherein the step of locking the gate includes moving a stop member upon movement of the nudger to a position away from the sheets. 
     
     
         11 . The method defined in  claim 6 , wherein the step of releasably locking the gate in closed position includes moving the gate under the force of gravity to an initial position upon unloading of the receptacle and moving a locking member under the force of gravity.