System and method for consistent paper movement

Abstract

A system and method for consistent paper movement includes a pick/feed motor configured to rotate a pick/feed roller of a print engine to deliver a sheet of paper to the registration nip of a registration roller. A first sensor and a second sensor disposed in the paper path between the pick/feed roller and the registration roller detect the leading edge of the paper. A controller receives sensor data from the first and second sensors and compares the sensor data with expected times for receiving the sensor data. When the received sensor data indicates that the paper is lagging or leading, the controller calculates a period of time to drive the drive the pick/feed motor at a higher or lower speed to compensate for the lagging or leading of the paper.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a registration motor configured to rotate a registration roller of an associated print engine;   a pick/feed motor configured to rotate a pick/feed roller of the print engine and deliver a sheet of paper to the registration roller;   a first sensor disposed in a paper path between the pick/feed roller and the registration roller configured to detect a leading edge of the paper;   a second sensor disposed in the paper path configured to detect the leading edge of the paper subsequent to the first detector; and   a controller configured to
 receive a sensor data from the first sensor, 
 compare the sensor data with an expected time for receiving the sensor data, 
 determine, based on the compare operation, when the received sensor data indicates that the paper is lagging, 
 calculate a period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper, 
 operate the pick/feed motor at a higher speed for the calculated period of time. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the pick/feed motor is a variable speed pick/feed motor and wherein the controller is further configured to calculate the higher speed necessary to compensate for the lagging of the paper. 
     
     
         3 . The apparatus of  claim 2 , wherein the controller is further configured to
 determine, based on the compare operation, when the received sensor data indicates that the paper is leading,   calculate a second period of time to operate the pick/feed motor at a lower speed to compensate for the leading of the paper,   calculate the lower speed necessary to compensate for the leading of the paper, and   operate the pick/feed motor at the calculated lower speed for the second calculated period of time.   
     
     
         4 . The apparatus of  claim 1 , wherein the controller is further configured to
 determine, based on the compare operation, when the received sensor data indicates that the paper is leading,   calculate a second period of time to stop the pick/feed motor to compensate for the leading of the paper,   stop the pick/feed motor for the second calculated period of time.   
     
     
         5 . The apparatus of  claim 1 , wherein the controller is further configured to
 receive a second sensor data from a second sensor sensor,   compare the second sensor data with an expected time for receiving the second sensor data,   determine, based on the compare operation, when the received second sensor data indicates that the paper is lagging,   calculate a second period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper, and   operate the pick/feed motor at a higher speed for the second calculated period of time.   
     
     
         6 . The apparatus of  claim 1 , wherein the controller is further configured to
 determine a deskew time,   rotate the registration motor and the registration roller in a reverse direction to deskew the paper for the determined deskew time, and   rotate the registration motor and registration roller in a forward direction, after the deskew time, to advance the paper to an image transfer unit of a printer.   
     
     
         7 . The apparatus of  claim 1 , further comprising:
 a motor driver configured to
 receive a pulse width modulated signal and a direction signal from the controller for each of the registration motor and the pick/feed motor, and 
 drive the associated registration motor and the pick/feed motor in accordance with the associated pulse width modulated signal and the direction signal. 
   
     
     
         8 . The apparatus of  claim 7 , further comprising:
 a multifunction peripheral including
 the controller further comprising a processor and an associated memory, and 
 a print engine comprising
 the registration roller, 
 the registration motor, 
 the pick/feed roller, 
 the pick/feed motor, 
 the first sensor, 
 the second sensor, and 
 the motor driver. 
 
   
     
     
         9 . A multifunction printer, comprising:
 a print engine operable to perform a print operations, comprising
 a registration motor configured to rotate a registration roller, 
 a pick/feed motor configured to rotate a pick/feed roller configured to deliver a sheet of paper to the registration roller, 
 a first sensor disposed in a paper path between the pick/feed roller and the registration roller configured to detect a leading edge of the paper, and 
 a second sensor disposed in the paper path configured to detect the leading edge of the paper subsequent to the first detector; and 
   a controller configured to
 operate the pick/feed motor at a first speed, 
 receive sensor data from the first sensor and the second sensor, 
 compare a receive time of the sensor data with an expected receive time, 
 determine, based on the compare operation, when the receive time of the sensor data indicates that the paper is leading or lagging, 
 calculate a period of time to operate the pick/feed motor at a second speed to compensate for the leading or lagging of the paper, 
 operate the pick/feed motor at a second speed from normal for the calculated period of time. 
   
     
     
         10 . The multifunction printer of  claim 9 , wherein second speed is selected from the group consisting of a variable higher speed, a variable lower speed, a higher speed, and a stopped or zero speed. 
     
     
         11 . The multifunction printer of  claim 9 , wherein the controller is further configured to
 determine a deskew time,   rotate the registration motor and the registration roller in a reverse direction to deskew the paper for the determined deskew time, and   rotate the registration motor and registration roller in a forward direction, after the deskew time, to advance the paper to an image transfer unit of a printer.   
     
     
         12 . The multifunction printer of  claim 9 , wherein the motor driver is configured to
 receive a pulse width modulated signal and a direction signal from the controller for each of the registration motor and the pick/feed motor, and   drive the associated registration motor and the pick/feed motor in accordance with the associated pulse width modulated signal and the direction signal.   
     
     
         13 . A method, comprising:
 driving, by a controller, a pick/feed motor at a normal speed to place a sheet of paper in a paper path of a print engine;   sensing, by a first sensor, a leading edge of the sheet of paper;   sending, by the first sensor, a first signal to a controller associated with the print engine;   sensing, by a second sensor, the leading edge of the sheet of paper;   sending, by the second sensor, a second signal to the controller;   calculating, by the controller, a first expected time associated with the first signal and a second expected time associated with second signal;   receiving, by the controller, the first signal;   comparing, by the controller, an arrival time of the first signal with the first expected time;   determining, by the controller and based on the compare operation, when the paper is lagging;   calculating, by the controller, a period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper; and   operating, by the controller, the pick/feed motor at the higher speed for the calculated period of time.   
     
     
         14 . The method of  claim 13 , wherein the pick/feed motor is a variable speed pick/feed motor and further comprising:
 determining the higher speed based in conjunction with the operation of calculating the period of time to operate the pick/feed motor at a higher speed.   
     
     
         15 . The method of  claim 13 , further comprising:
 determining, by the controller and based on the compare operation, when the paper is leading;   calculating, by the controller, a second period of time to operate the pick/feed motor at a lower speed to compensate for the leading of the paper; and   operating, by the controller, the pick/feed motor at the lower speed for the calculated second period of time.   
     
     
         16 . The method of  claim 15 , wherein the pick/feed motor is a variable speed pick/feed motor and further comprising:
 calculating, by the controller, the lower speed necessary to compensate for the leading of the paper; and   operating, by the controller, the pick/feed motor at the calculated lower speed for the second calculated period of time.   
     
     
         17 . The method of  claim 13 , further comprising:
 determining, by the controller and based on the compare operation, when the paper is leading;   calculating, by the controller, a second period of time to stop the pick/feed motor to compensate for the leading of the paper; and   stopping, by the controller, the pick/feed motor for the calculated second period of time.   
     
     
         18 . The method of  claim 13 , further comprising:
 receiving, by the controller, the second signal;   comparing, by the controller, an arrival time of the second signal with the second expected time;   determining, by the controller and based on the compare operation, when the paper is lagging;   calculating, by the controller, a second period of time to operate the pick/feed motor at a higher speed to compensate for the lagging of the paper; and   operating, by the controller, the pick/feed motor at the higher speed for the calculated second period of time.   
     
     
         19 . The method of  claim 18 , further comprising:
 determining, by the controller and based on the compare operation, when the paper is leading;   calculating, by the controller, a third period of time to operate the pick/feed motor at a lower speed to compensate for the lagging of the paper; and   operating, by the controller, the pick/feed motor at the lower speed for the calculated second period of time.   
     
     
         20 . The method of  claim 18 , further comprising:
 determining, by the controller and based on the compare operation, when the paper is leading or lagging;   calculating, by the controller, a deskew time to compensate for the leading or lagging;   rotating, by the controller, the registration motor in a reverse direction to cause the registration rollers to deskew the paper for the calculated deskew time; and   rotate the registration motor in a forward direction, after the deskew time, to advance the paper by the registration rollers to an image transfer unit of a printer.