Printer uses Kerr cell as light shutter for controlling the print on photosensitive paper. Applied to output data transfer, the information transfer rate of graphic computer printers could be increased to speeds approaching the data transfer rate of computer central processors /5000 to 10,000 lines per minute/

Stephens, J. W.

English

NASA Technical Reports Server

October 1970	 Brief 70-10484 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Concept for High Speed Computer Printer 
Most printers currently use mechanically actuated 
type. Magnetic ink is often used, and is sprayed toward 
the paper, shaping the different characters magneti-
cally. These printers are very fast, rated at 132 charac-
ters per line, and 1200 lines per minute. 
Photo Sensitive 
Paper Transport
Rotating 
Prism and 
Motors 
. High Voltage 
Bias Modulator 
Memory 
Printer 
Computer Generator 
Input
Simplified Mechanical Schematic 
This new conceptual design for a high speed com-
puter printer uses a Kerr cell as a light shutter for con-
trolling the print on photosensitive paper. Applied to 
output data transfet, the information transfer rate 
of graphic computer printers could be increased to 
speeds approaching the data transfer rate of computer 
central processors (5000 to 10,000 lines per minute).
This information should interest designers and manu-
facturers of peripheral computer equipment, com-
puterized newspaper and manuscript publication 
industries, and has possible application for rapid re-
porting of stock market quotations. 
The printer operates by projecting a modulated 
light beam which is scanned across photosensitive 
paper or film. Several scans are required to form the 
complete characters in the line of information. The 
unique feature of this printer is the use of the light 
valve (Kerr Cell) for character definition as direct 
output of the computer. However, several other dis-
play methods are possible. One method would be to 
group several of these light valves; by careful selection 
of which valve is either on or off, a complete character 
could be formed and printed. 
As shown in the figure, the printer is composed of 
separate components. The heart of the printer is the 
light valve or electronic shutter, used to modulate 
the light beam which forms the characters to be print-
ed. The actual time for the shutter or light valve to go 
from fully closed through fully open back to fully 
closed is approximately 15 x 10 9seconds (15 nano-
seconds), or it could cycle 66 x 106 times in one 
second. Therefore, the limiting factor is not the 
shutter, but the sensitivity of the paper or film. 
The optical system of the printer is a straightforward 
projection system; if space did not allow, a fiber 
optics system could be utilized for placement of the 
light valve at a more convenient remote location. The 
transport system encompasses the mechanism to store 
the photosensitive paper or film, move it past the print-
ing point, process the printed paper (either wet or dry), 
and maintain a synchronous speed with the electronic 
printing process.
(c*ntinued overleaf) 
Light 
Valve'... 
.	
Collimator 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately ownedrights.
https://ntrs.nasa.gov/search.jsp?R=19700000467 2020-03-17T00:31:17+00:00Z
The last major components of the computer printer 
are the required electronic circuits. The memory 
printer contains the necessary electronics to accept 
and retain a complete line of information from the 
computer. This information is retained until the 
character generator acts upon. it, then resets itself 
for the next line of information. The memory printer 
also supplies the necessary synchronization pulses to 
the prism and transport servo system. 
The prime electronic circuit is the character genera-
tor which supplies the modulation signal to the high 
voltage bias modulator during the scan, forming that 
portion of the individual characters which appears 
in the particular scan line. The output of this character 
generator controls the high voltage bias, which fur-
nishes the necessary voltage stress across the light valve 
to actuate the polarization characteristic.
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: B70-10484 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: J.W. Stephens of

The Boeing Company 
under contract to

Kennedy Space Center
(K SC- 10373) 
Brief 70-10484	 Category 09


Concept for high speed computer printer

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