COLOR SEQUENCING FOR INTERMEDIATE XEROGRAPHY
Original Publication Date: 1992-Apr-30
Included in the Prior Art Database: 2004-Apr-06
Xerox Disclosure Journal
A color sequencing scheme for use in intermediate xerographic printing and copying applications is disclosed. Color xerography may use one of three development schemes for forming an image on paper - sequential, simultaneous and intermediate. The sequential method transfers each color from a photoreceptor 1 to a paper copy sheet 2 individually in successive steps affording a less than quantitative transfer efficiency. A color shifting problem does not arise when the extent of the transfer of each color is comparable. The sequential method is shown in Fig. 1. The intermediate transfer method shown in Fig. 2, comprises compiling each unfused color image 3 on an intermediate transport member 4 prior to transfer of a complete color image to a copy sheet 2. Similarly, the simultaneous method compiles each unfused color image on a photoreceptor before transferring to a copy sheet or an intermediate. The intermediate method may experience serious color shifting problems that arise from non-uniform transfer efficiencies, for example, a color 5 in contact with an intermediate may partially or preferentially remain on the intermediate rather than completely transferring to the copy sheet. To overcome this potential transfer problem, a color sequencing scheme is disclosed that compensates for incomplete transfer and minimizes color shift. As shown in Fig. 3, the relative quantities of magenta (M), yellow (Y) and/or cyan (C) toner required to produce desired colors are given. These toner orderings and amounts may afford greater latitude for color transfer subsystems. A preferred multi-color development sequence for overcoming incomplete intennediate-to-paper transfer is C/M/y/I where I represents the intermediate transfer member. This sequence is preferred because other permutations give rise to problem colors. When a four color black (K) is included in the development package a preferred sequence is C/M/Y/K/I.