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:
Mar. 04, 1986
Filed:
Nov. 23, 1983
Samuel C Harris, Jr, Waynesboro, VA (US);
Genicom Corporation, Waynesboro, VA (US);
Abstract
A ribbon tension control for controlling the tension of ribbon traveling between a rotating supply spool and a rotating take-up spool varies the amount of braking torque applied to the supply spool to hold ribbon tension constant as the distribution of ribbon between the spools changes. A generator rotationally coupled to the supply spool produces braking torque to resist the rotation of the spool when the generator windings are electrically loaded. The loading of the generator is controlled by processing feedback signals emitted by the generator to provide periodic load switching signals. Processing of the feedback signal is accomplished in the exemplary embodiment by a drag lookup table which is addressed by the feedback signal. The drag lookup table produces a duty cycle value which is used to determine the duty cycle of the switching signal, which, in turn, controls the electrical loading of the generator. Because electrical loading of the generator at the switching signal rate modulates the feedback signal which it emits, the period of the switching signal is sufficiently different from that of the feedback signal to permit separation of the feedback signal from the switching signal.