While the exemplary embodiment is particularly directed to the art of digital image processing, and will be thus described with specific reference thereto, it will be appreciated that the exemplary embodiment may have usefulness in other fields and applications.
By way of background, serial and modular image rendering (or printing) architectures (and parallel printing architectures to some extent) enable printing on one page using more than one print engine. For instance, a printing system could be used for enhanced color printing. See, for example, US 2006/0222378 A1, by Paul C. Julien, in which highlight colors, gamut extension toners, and clear coats are printed with a second print engine. Other printers utilize more than four colorants in their printing processes.
However, print quality can suffer from misregistration defects in certain serial, modular and parallel printing architectures. Image rendering (or printing) processes are physical in nature. That is, image rendering processes rely on physical structures which can influence rendered image quality and consistency. For instance, variation in phosphor quality or density in a cathode ray tube (CRT) or plasma display, light emitting diode (LED) efficiency in an LED display, and/or spatial variation in the light output of a fluorescent back light in a liquid crystal display (LCD) can cause color appearance variations across the surface of a display device. In printing systems, physical alignments, component tolerances, wear and component age can influence the uniformity with which colorants such as inks and toners are laid down across the surface of print media.
Further, in a printer/copying machine where toner is fixed to a sheet, moisture is evaporated by the influence of heat when an image is fixed on a sheet and the sheet is shrunk, or the sheet is stretched by the influence of pressure of the fixing processing. Additionally, sheets may be out-of-skew or out-of-registrater. Rotation and slanting may occur in the case where printing is carried out using an intermediate transfer member. In that case, a difference in nip balance in an axial direction of a transfer part causes a difference between a direction in which an image is transferred and a traveling direction of a sheet, and the rotation or slanting can occur. When such slanting/rotation occurs, an image printed on the sheet may become trapezoid or fan-shaped.
Additionally, using serial and parallel printing to incorporate additional colorants or image content on a previously printed sheet can result in color halos around printed objects if the image printed by the second engine is not registered with the first printing.
Thus, the exemplary embodiments relate to a new and improved method and apparatus that resolves the above-referenced difficulties and others.