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Print Emitter
The print emitter is a stationary board with a
land pattern and a 4.25 MHz oscillator. The land
pattern simulates the primary winding of an air
core transformer.
The print emitter pickup is mounted on the bot-
tom of the print carrier and slides along the length
of the print emitter. The pickup consists of four
separate land patterns and associated amplifier de-
tector trigger circuits. The land patterns of the
print emitter pickup simulate the secondary wind-
ings of an air core transformer.
Print emitter signals are used by the system to
determine:
• When the print head is in the left margin.
•
How far the print head is from the left margin.
•
Which direction the print head is moving.
•
When to fire the print magnets.
Land patterns denoted by
D
and
0
are at right
angles to the patterns denoted by
D, fJ
and
D .
When the print emitter pickup enters the
left margin area, land pattern Dof the print
emitter pickup moves directly underneath land
pattern
II
of the print emitter. As a result of
this alignment, energy is coupled from the pri-
mary winding of the print emitter into the sec-
ondary winding of the print emitter pickup and
causes a level change at the output of the amplifier
detector trigger circuit. This level change signals
the system that the print head is in the left margin
area.
9-4
Print Carrier
I
\
CiIDf
, - - - - - - - - - - - - ,
Print Emitter
Print Emitter Pickup
Pads provide 0.015 inch (0.38 mm)
maximum clearance.
Print Emitter Pickup
Print Emitter
i
r
0.030 inch (0.76 mm)
I
Oscillator
------------------------------------
I
I
I
I
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1(10
I
I
I
I
I
I
I
D
~---
Print Emitter Pickup
I
I
---
Four
p.
E·
3
I
I
L L - - - -
A
IT
nnt
mltter
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I
L ________ ::::
=
~
=
mp
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ler Pri nt Em itter 2
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L
~
=- =- = =
=
=-
=
--=-
-=-
--=-
-=--
Detector
l~~~~:~ ::~:1
Print Emitter Pickup in Left Margin
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