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. 06, 1977
Filed:
Mar. 01, 1976
Gary B Ollendick, Chicago, IL (US);
Teletype Corporation, Skokie, IL (US);
Abstract
A circuit for controlling a graphic display printer wherein a paper sheet is wrapped about a rotating drum and maintained in place thereon by a vacuum. The length of the paper sheet is slightly longer than the circumference of the drum and thus defines a tangentially projecting flap. A sensor detects passage of the flap and in response to the initial detection, a counter is started having a cycle corresponding to one rotation of the drum. Selected states of the counter are digitally compared to the output of the flap sensor. After the rotational position of the flap has been determined twice for each of three successive drum revolutions, a paper validation signal is generated indicating that the paper is properly wrapped about and rotating with the drum. In response to the validation signal, printing is started. The circuit also includes means for preventing writing on the flap by correctly locating the copy with respect to top of paper and for maintaining a straight, first, print line irrespective of the characteristics of the paper edge or its positional sensing variations.