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:
Feb. 28, 1978
Filed:
Jul. 08, 1976
Prentice I Robinson, Pelham, NH (US);
Thomas T Butterfield, Chester, NH (US);
Centronics Data Computer Corporation, Hudson, NH (US);
Abstract
An opaque flag mounted upon a printer carriage assembly interrupts the light emmitted by a LED from reaching a phototransistor when at the left-hand margin of the paper document. The carriage starts to move and when it reaches constant print velocity, the opaque flag moves away from the LED and the phototransistor to activate the phototransistor to trigger a gated oscillator to generate pulses of very uniform size and shape and preferably of a 50% duty cycle. The leading and trailing edges of the pulses from the gated oscillator generate strobe and delay strobe pulses of shorter pulse duration which, in turn, energize the wire actuating solenoids forming full-step and half-step dots the full-step dots creating characters within a 5 .times. 7 dot matrix and both the half-stepand full-step dots being forming characters within a 9 .times. 7 dot matrix. When printing is completed, a PRIME signal resets and abruptly stops the gated oscillator. The carriage is returned to the left-hand margin doing so, moving the flag between the LED and the phototransistor to decouple the drive from the carriage assembly before reaching the left-margin and enable the carriage to coast to a stop. The sequence is repeated for each line of print.