Method for measuring beam to beam stitch error in the presence of variable width beams
AssigneeXerox Corporation
InventorJames P. Calamita
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Abstract
According to aspects of the embodiments, there is provided process and architecture for enabling multiple digital micromirror devices (DMDs) that include optical modulation elements configured to modulate light outputting from a light source, and a projection unit configured to project light modulated by the optical modulation elements on a printing plate. Image defects due to misalignment in the cross-process direction of the output from the DMDs are discovered by using a single test pattern image and combined with knowledge of how individual pixels are rendered to register printing elements which can render a variable number of pixels. Misalignment errors can be corrected by selecting a different set of mirrors for a given DMD.
Claims20
A method of registering printing elements in an image formation apparatus to render an image from a variable number of pixels, the method comprising:
- loading instructions to a processor for stitching parallel light beams from the printing elements into a single image that can be formed as a series of marks on an imaging member;
- wherein the parallel light beams are directed by at least two digital micro mirror devices (DMDs) each comprising a plurality of mirrors such that the parallel light beams are reflected out onto the imaging member;
- loading at the processor a test pattern image to be rendered as the series of marks on the imaging member;
- using a table that has been modified based on the loaded instructions to determine which of the plurality of mirrors is to produce the series of marks;
- using the table to render the test pattern image on the imaging member;
- analyzing the rendered image to determine if a stitch error will occur;
- when a stitch error is determined, then correcting the stitch error by modifying at least one of the table and the processor;
- wherein modifying the processor is modifying the loaded instructions.
An image formation apparatus, comprising:
- a member defining an imaging surface;
- at least two digital micro mirror devices (DMDs), each disposed over a surface of the member defining an imaging surface at different angular positions, so as to project a beam onto the surface from different angles;
- a processor;
- and
- a storage device coupled to the processor, wherein the storage device contains instructions operative on the processor to register projected variable number of pixels from the DMDs by:
- loading instructions for stitching parallel light beams from the DMDs into a single image that can be formed as a series of marks on an imaging member;
- wherein the parallel light beams are directed by the at least two digital micro mirror devices (DMDs) each comprising a plurality of mirrors such that the parallel light beams are reflected out onto the imaging member;
- loading a test pattern image to be rendered as the series of marks on the imaging member;
- using a table that has been modified based on the loaded instructions to determine which of the plurality of mirrors is to produce the series of marks;
- using the table to render the test pattern image on the imaging member;
- analyzing the rendered image to determine if a stitch error will occur;
- when a stitch error is determined, then correcting the stitch error by modifying at least one of the table and the processor;
- wherein modifying the processor is modifying the loaded instructions.
Dependencies are inferred from the claim text.