METHOD FOR DETERMINING ELECTRO-PHOTOGRAPHIC PROCESS CONTROL SET POINTS
A method for determining process control set points for printing an image with clear and color toners, the method includes determining a first set of clear toner process control set points for printing a target height of clear toner on a receiver; determining a second set of color toners process control set points for printing color toner with clear toner lay-down determined by the first set of process control parameters which achieves a target color profile; estimating a new set of values for the first set of clear toner process control set points which provides a uniform topography; modifying the first clear toner and second color toners set of process control set points for printing color toners with the clear toner lay-down, using the estimated new set of first process control set points and the determined second set of color toners process control set points as starting points, for providing the target color profile and the uniform topography.
1 . A method for determining process control set points for printing an image with clear and color toners, the method comprising:
(a) determining a first set of clear toner process control set points for printing a target height of clear toner on a receiver;
(a1) depositing clear toner on a target substrate, and measuring the height of the clear toner over a range of clear toner laydowns;
(b) determining a second set of color toners process control set points for printing color toner with clear toner lay-down determined by the first set of clear toner process control set points which achieves a target color profile;
(b1) measuring the step height on the color patch corresponding to 100% laydown;
(c) estimating a new set of values for the first set of clear toner process control set points which provides a uniform topography;
(d) modifying the first set of clear toner and second set of color toners process control set points for printing color toners with the clear toner lay-down, using the estimated new set of first clear toner process control set points and the determined second set of color toners process control set points as starting points, for providing the target color profile and the uniform topography.
2 . The method as in claim 1 , wherein the target height is greater than a maximum height of a four color toner lay-down that can be achieved in a toner printing process.
3 . The method as in claim 2 , wherein only a V o (photoreceptor voltage) set point of the first set of clear toner process control set points is adjusted.
4 . The method as in claim 1 , wherein only an exposure profile of the second set of color toners process control set points is adjusted.
5 . The method as in claim 1 , wherein modifying the first clear toner and second color toners set of process control set points includes one or more iterations until the color profile and the topography convergence to the target profile and the uniform topography within tolerance ranges.
6 . The method as in claim 5 comprising:
measuring the topography of the clear toner in combination with the color toner across the image;
wherein the tolerance range for the uniform topography is 2 μm.
7 . The method as claim 1 further including the subroutine of determining a third set of color toners process control set points for printing color toner with no clear toner lay-down.