Alphameric/facsimile printer receives serial digital data in the form of a specified number of bits per group and prints it on thermally sensitive paper. A solid state shift-register memorizes the incoming serial digital data

Perkins, R. D.

Perkins, W. E.

Taylor, J. W.

Thomas, D. G.

English

NASA Technical Reports Server

December 1967	 Brief 67-10572 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Teleprinter Uses Thermal Printing Technique 
An alphameric/facsimile printer receives serial digi-
tal data in the form of a specified number of bits 
per group, with the time duration of each bit a speci-
fied number of milliseconds. Each group of bits is 
followed by a data pause which will last a specified 
number of milliseconds. The printer prints a black 
dot on the thermally sensitive paper for each digital 
"one" received and prints nothing for each digital 
"zero" it receives. The first data bit per group is 
placed at the left edge of the paper and each suc-
ceeding bit is placed a specified distance to the right 
of the preceding dot position on the paper. 
The thermal print head is composed of the same 
number of printing elements as there are bits per 
group. These print elements are arranged in a single 
line oriented across the specified width of the paper. 
Electrically, these print elements are energized in con-
venient subgroups. Each element in a subgroup has a 
common electrical terminal with other elements in the 
subgroup, and this common terminal is grounded by a 
solid state switch when it is the proper time for one 
or more of the elements in the subgroup to be heated 
in accordance with the incoming signal. The other 
terminal of each thermal element is connected via the 
gate terminal, a silicon-controlled rectifier (SCR), to a 
solid state shift-register stage which momentarily 
memorizes the incoming serial digital data. The shift 
register can memorize data for several subgroups of 
thermal elements; so at the time it is interrogated, it 
contains data for several subgroups of thermal 
elements. 
A dc voltage is applied continuously to the anode 
of the SCR. If the cathode of the SCR is grounded 
ant4 ;r thnr k a "rin p" n thp cbft rpaiotpr ctate tt
which the gate of the SCR is connected, the SCR will 
conduct. A print pulse is routed through an "AND" 
gate along with the grounder signal to the base of 
the grounder transistor. The print pulse turns on the 
grounder for an appropriate number of milliseconds. 
Since one side of a thermal printing element is con-
nected to the cathode of the SCR, current will pass 
through the thermal element to the common electrical 
terminal for the group if the common is grounded by 
the grounder transistor at that time. 
If there is a "zero" in the shift register stage to 
which the gate of the SCR is connected, the SCR will 
not conduct when the print pulse turns on the 
grounder transistor and, consequently, no current will 
flow in the thermal element connected to the SCR 
cathode. 
The roll or fan-fold paper coated with a thermally 
sensitive dye is stored in or near the teleprinter 
assembly. The paper is routed between a pressure 
roller and the thermal head assembly. The paper is 
then pulled around the pressure roller as they both 
turn in discrete angular steps. The paper then passes 
through guides behind a preview window to a slot in 
the front panel where it exits for viewing by the 
observer. 
Note: 
Inquiries concerning this invention may be directed 
to:
Technology Utilization Officer 
Manned Spacecraft Center 
Houston, Texas 77058 
Reference: R67-l0572 
.--- ----- .
	
(continued overleaf) 
MW
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 owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000571 2020-03-11T21:02:26+00:00Z
Patent status: 
Title to this invention has been waived under the 
provisions of the National Aeronautics and Space 
Act (42 U.S.C. 2457 (f)), to The National Cash 
Register Company, Menlo Park, California 94025. 
Source: R. D. Perkins, W. E. Perkins, 
D. G. Thomas, and J. W. Taylor 
of The National Cash Register Company 
under contract to 
Manned Spacecraft Center 
(M SC- l 1327) 
Brief 67-10572	 Category 61


Teleprinter uses thermal printing technique

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