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:
Jan. 28, 1997
Filed:
Jan. 31, 1994
Samuel A Stodder, Encinitas, CA (US);
Paul J Wield, Poway, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
The invention uses two very inexpensive rotary encoders in combination--a close-coupled one (or more) for high accuracy, and a remote-coupled one for high resolution. High-accuracy information is then combined with high resolution information in a digital processing system to yield composite information that is high in both accuracy and resolution. This information can be used to establish image positioning on a print medium. The overall system cost is lower than with an equivalent single encoder. Insidious cyclical errors in the coupling system (gear train or the like) are removable without expensive high tolerances and assembly or test fixtures. Residual cyclical error due to eccentric mounting or other error in the direct-coupled encoder scale also can be substantially removed, if desired, by adding another one or more encoders reading that scale, and suitably combining the information about that scale from the different sensors. The information is combined in such a way that the systematic cyclical errors cancel--or are quantified for use in explicit correction.