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:
Aug. 21, 1990
Filed:
Sep. 11, 1987
Kiyosuke Suzuki, Saitama, JP;
Michihiro Hino, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A PWM (Pulse Width Modulation) control circuit for printing apparata comprises a memory for storing digitized image data, a main converter connected to the memory for converting upper bits of the digitzed image data into a main pulse-width modulated signal based on a first unit time duration, a sub-converter connected to the memory for converting the rest of the bits of the digitized image information into a sub pulse-width modulated signal based on a second unit time duration, and a drive circuit connected to the main converter and sub-converter for generating the driving signal in accordance with the main pulse-width modulated signal and sub pulse-width mnodulated signal. The amount of transferred digital tone data per horizontal line of a whole printing screen is reduced and the color concentration characteristics of the thermal head are appropriately maintained within an acceptable range.