Direct color consistency control for xerographic printing

The digital color printing process can be described by the color reproduction characteristics (CRC) function that maps the input color to the output color. The CRC map is high dimensional in that there are potentially high number of output colors that a digital color printing process can reproduced. To maintain color consistency, it is desirable to have the CRC to match the desired CRC map at all times. In this paper, we first propose an effective sparse sensing approach known as time-sequential sampling to retrieve the time-varying CRC using small number of color samples at each print cycle. The availability of this information enables formulation of a 2-STAGE process level control system: STAGE-I is a curve fitting rvbust control that makes best use of the xerographic actuators and STAGE-II is a image feedforward compensation scheme. The key contribution of this paper is in proposing direct CRC control(full closed loop) for maintaining color consistency, as opposed to stabilizing the TRC of all the primary color separations (i.e. Cyan, Magenta, Yellow and Black) in previous works. Effective CRC stabilization is demonstrated using the proposed approach while requiring small number of color samples.