A black printhead is installed in a scanning carriage with at least one primary color printhead on both sides of the black printhead. To reduce the drying time of a printed black ink pattern and to achieve other benefits, a first one of the primary color inks underprints the black ink in a first scan...http://www.google.com/patents/US6244687?utm_source=gb-gplus-sharePatent US6244687 - Mixing overprinting and underprinting of inks in an inkjet printer to speed up the dry time of black ink without undesirable hue shifts
