The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 2000
Filed:
Oct. 19, 1998
Girmay K Girmay, La Mirada, CA (US);
Xerox Corporation, Stamford, CT (US);
Abstract
A single pass ROS system provides a plurality of latent images which may subsequently be developed in different colors. A method and apparatus is provided for aligning ROS units in a single pass printing system, so that each ROS unit is aligned along the process or X-axis. After this alignment, the images formed by each ROS unit will be in proper registration within the prescribed tolerances. A signal in a closed feedback loop regulates the angular velocity and phase of the rotating polygon mirror of the first ROS unit. The same signal is also the reference signal to the feedback loops of the other rotating polygon mirrors of the other ROS units to synchronize all of the rotating polygon mirrors. The position of the scan lines formed by their respective ROS units are fixed relative to one another and thus, lacking any other error sources, are registered in the process direction. A proportional integral derivative controller, the motor polygon assembly and a speed detector form the synchronization system for each ROS unit. The proportional integral derivative controller produces the synchronized signal for the MPA as a function of the proportional feedback signal, the integral feedback signal and the differential feedback signal. The speed detector in the feedback loop has an invertor, a feedback gain and a zero order hold to convert the velocity/phase signal from the MPA into a feedback signal. The feedback signal, a weighted summed feedback signal from a feedback adder from all the ROS units and a reference signal are input to the proportional integral derivative controller.