Patent ID: 7158732

Claim:
A method of controlling the tonal reproduction curve (TRC) and maintaining toner concentration (TC) within the latitude range of an electrophotographic print engine with a TC target, the method comprising: setting the level of a trigger point, wherein the trigger point comprises an actuator boundary at which a TC move will be triggered at some pre-determined level away from the actuator's limit; receiving data from a sensor; determining whether any one of a first set of conditions exists; setting the TC target to tone TC up by delta TC, where any one of the first set of conditions exists, wherein the first set of conditions includes V dev >(V devMax −V devMargin ), |V c |>(|V c Max |−|V c Margin |), |V m |>(|V mMax |−|V mMargin |), a dark patch with Cin between 70% and 100% is too light and out of the tolerance range continuously for a predetermined number of times, and the dark patch is light and a mid-tone patch with Cin between 40% and 60% is too dark and out of the tolerance range continuously for a predetermined number of times; determining whether any of any of a second set of conditions exists; and setting the TC target to tone TC down by delta TC, where any one of the second set of conditions exists, wherein the second set of conditions includes |V c |<(|V c Min |+|V cMargin |), |V m |<(|V mMin |+|V mMargin |), a dark patch with Cin between 70% and 100% is too light and out of the tolerance range continuously for a predetermined number of times, and the dark patch is light and a mid-tone patch with Cin between 40% and 60% is too dark and out of the tolerance range continuously for a predetermined number of times.