Method and apparatus for determining and updating a photoreceptor belt steering coefficient in a belt tracking system
AssigneeXerox Corporation
InventorsSsujan Hou, Jacob N. Kluger
Life of this patent
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Abstract
An electrophotographic printing machine is provided having an endless photoreceptor belt arranged to move in a predetermined path through a plurality of processing stations. The apparatus is used in conjunction with a method for automatically and repeatedly measuring and updating a steering coefficient used in an automatic steering mode. The method includes centering the belt and finding the average "in" belt walk and "in" belt walk rate and the average "out" belt walk and "out" belt walk rate, in order to determine the steering control coefficient. The method allows for a single machine to have its steering coefficient repeatedly updated.
Claims23
An apparatus for controlling lateral alignment of a belt arranged to move in a predetermined path, the apparatus comprising:
- a roll arranged to support a portion of the belt passing thereover;
- a pivotable means for rotatably supporting said roll;
- a motor, connected to said pivotable means such that operation of said motor alters an orientation of the roll by pivoting said pivotable means in a desired direction;
- a means for automatically controlling operation of said motor in order to maintain the belt on said roll within preset position parameters, said means for automatically controlling including,
- a belt edge detector for acquiring belt tracking data, and
- a motor controller for actuating and controlling said motor based on the belt tracking data acquired;
- and
- a means for initializing said automatically controlling means said means for initializing including,
- a means for determining a tilt range of said roll,
- a means for determining a linear displacement of an end of said pivotable means, and
- a means for determining a number of revolutions of said roll.
An apparatus for controlling lateral alignment of a belt arranged to move in a predetermined path, the apparatus comprising:
- a roll arranged to support a portion of the belt passing thereover;
- a pivotable means for rotatably supporting said roll, said pivotable means including,
- a yoke on which said roll is rotatably mounted,
- a spindle to which said yoke is secured, and
- a frame on which said spindle is mounted;
- a motor, connected to said pivotable means such that operation of said motor alters an orientation of the roll by pivoting said pivotable means in a desired direction;
- a means for automatically controlling operation of said motor in order to maintain the belt on said roll within preset position parameters, said means for automatically controlling including,
- a belt edge detector for acquiring belt tracking data, and
- a motor controller for actuating and controlling said motor based on the belt tracking data acquired;
- a means for initializing said automatically controlling means;
- and
- a means for manually pivoting said yoke.
An apparatus for controlling operations upon a belt, comprising:
- a means for sensing an edge pattern of said belt, said edge pattern comprising a cross-track position and an in-track position of said belt;
- a means for generating signals representing sensed edge pattern data;
- a means for storing said edge pattern data;
- a means for comparing said sensed edge pattern data;
- and,
- a means for steering said belt to a desired edge position from several belt revolutions when the sensed edge position exceeds a pre-determined allowed limit value.
An electrophotographic printing machine of a type having an endless photoreceptor belt arranged to move in a predetermined path through a plurality of processing stations disposed therealong, the machine comprising:
- a roll arranged to support a portion of the endless photoreceptor belt passing thereover;
- a yoke on which said roll is rotatably mounted;
- a spindle to which said yoke is secured;
- a cam secured to an end of said yoke;
- a cam follower in operative engagement with said cam;
- a motor, connected to said cam follower, for operating on said cam and pivoting said yoke on said spindle and hence orienting said roll in a desired direction;
- a means for automatically controlling operation of said motor in order to center the belt on said roll;
- said means for automatically controlling including, a belt edge detector for acquiring belt tracking data,
- a steering motor controller for actuating and controlling said motor based on the belt tracking data acquired, and
- a means for initializing said automatically controlling means;
- a means for initializing said automatically controlling means, said means for initializing including,
- a means for determining a tilt range of said roll;
- a means for determining a linear displacement of an end of said yoke, and
- a means for determining a number of revolutions of said roll.
A method for initializing a steering control of a belt moving along a path by operation of a motor, the belt being subject to lateral movement in a direction transverse to a direction of movement of the belt along the path, the method comprising the steps of:
- steering the belt to a preset position;
- turning the motor clockwise for N steps;
- measuring an average belt walk and rate of belt walk for X belt revolutions;
- steering the belt back to the preset position;
- turning the motor counterclockwise for N steps;
- measuring an average belt walk and rate of belt walk for X belt revolutions;
- and,
- determining a steering control gain.
In an electrophotographic printing machine of a type having an endless photoreceptor belt arranged to move in a predetermined path through a plurality of processing stations disposed therealong, a method for automatically and repeatedly measuring and updating a steering coefficient used in an automatic steering mode employing a steering motor, to maintain the endless photoreceptor belt within predetermined parameters, the method comprising:
- engaging the automatic steering mode;
- steering the belt to a preset position;
- disengaging the automatic steering mode;
- turning the steering motor clockwise for N steps;
- measuring an average belt walk in and rate of belt walk in for X belt revolutions;
- reengaging the automatic steering mode;
- steering the belt back to the preset position;
- disengaging the automatic steering mode;
- turning the steering motor counterclockwise for N steps;
- measuring an average belt walk out and rate of belt walk out for X belt revolutions;
- and,
- determining the steering coefficient.
In an electrophotographic printing machine of a type having an endless photoreceptor belt arranged to move in predetermined path through a plurality of processing stations disposed therealong, a method for automatically and repeatedly measuring and updating a steering coefficient used in an automatic steering mode employing a steering motor, to maintain the endless photoreceptor belt within predetermined parameters, the method comprising:
- a) turning a steering roll to one side of the machine to remove possible backlash;
- b) turning the steering roll in a predetermined direction for N steering steps;
- c) locking the steering roll;
- d) running the belt for x revolutions;
- e) obtaining belt edge data from a belt edge detector during operation of step d;
- f) storing the belt edge data in an array at a fixed sample rate which is associated with a process encoder clock at n samples per belt revolution;
- g) calculating a slope B(i), intercept A(i) of linear regression for each of n data sets consisting of said Y(i), Y(n+i), Y(2n+i);
- h) determining a belt walk rate defined as, distance per revolution per said N steering steps, by taking an average of n slope data where, Y.sub.in =(.SIGMA.B(i)).div.n;
- i) calculating a correlation coefficient CC(i), which determines stability of the system, for each set of said Y(i), Y(n+i), Y(2n+i);
- j) repeating steps a through i to find Yout in the same manner Y.sub.in was found;
- and,
- k) determining steering coefficient, C.sub.steer, by taking an average of Yin and Your where, C.sub.steer =(Yin+Yout).div.2.
In an electrophotographic printing machine of a type having an endless photoreceptor belt arranged to move in predetermined path through a plurality of processing stations disposed therealong, a method for automatically and repeatedly measuring and updating a steering coefficient used in an automatic steering mode employing a steering motor, to maintain the endless photoreceptor belt within predetermined parameters, the method comprising:
- a) turning a steering roll, with clockwise rotation about its steering axis, to one side of the machine for a number of steering steps to remove possible backlash;
- b) further turning the steering roll in the same direction for N steering steps;
- c) locking the steering roll;
- d) running the belt for x revolutions;
- e) obtaining belt edge position data from a belt edge detector during operation of step d;
- f) storing the belt edge position data in an array (Y(i), i=1, xn) at a fixed sample rate which is associated with a process encoder clock at n samples per belt revolution;
- g) calculating a slope B(i), intercept A(i) of linear regression for each of n data sets consisting of said (Y(i), Y(n+i), . . . Y((x-1)n+i), i=1, n);
- h) determining a belt walk rate defined as, distance per revolution per said N steering steps, by taking an average of n slope data where steering coefficient (C.sub.cw), C.sub.cw =(.SIGMA.B(i)).div.n;
- i) calculating a correlation coefficient CC(i), which determines stability of the system, for each of n belt edge position data sets of step g;
- j) repeating steps a through i to find counter clockwise steering coefficient (C.sub.ccw), in the same manner C.sub.cw was found, for the steering roll turning with counter clockwise rotation about its steering axis;
- and,
- k) determining C.sub.cw or C.sub.ccw depending on the direction of the steering rotation.
Dependencies are inferred from the claim text.