Print Head - IBM 5256-1 Maintenance Information Manual

Print Head
Illustrated at the right is a side view of the print head
and an end view of the wire guide. The print head has
eight print wires arranged vertically 1 through 8, from
top to bottom. The character image dots are made by
the print wires as they strike the ribbon.
The circled area is a cross-section of a print wire
solenoid. The print wire" is attached to the armature
II.
When the coil
II
is energized by the print wire
driver, the armature is driven forward against the print
wire guide
B
driving the print wire against the ribbon.
The microprocessor pulses the print wire drive to fire
the print wire. When the pulse ends and the coil is
de-energized, the return spring
II
restores the armature
and print wire.
The Copy Control dial
II
on the printer adjusts the
distance from the print head to the platen to allow for
the thickness of the forms. The dial is set to 0 for
single-part forms and adjusted for legibility and reducing
ribbon smudging when using multiple-part forms.
As required by the character pattern, each wire can
strike the ribbon up to 4 times per character (for
example, print wire 5 when printing the character A).
Note that the character pattern is determined by the bits
that are on in the character generator. Print wires are
not fired at successive emitter pulses because time is
required to restore the solenoid armatures; at least 1
emitter pulse must intervene between firings of the
same wire. No more than 25 dots are used per
character.
Three emitter pulses are used for the space between the
characters.
Print Wires
~
.
1
;.-,.y..-r-r-T""""'"
2
3
4
5
6
7
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•
.
....
...,
t
8
Fire 4, 5, 6, 7 Fire 3
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1
...,
.-
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-
-
-
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A
t
Fire 2, 5 Fire 1
.-
-
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.-
-
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--1
--1
)'L
Fjre 2, 5
1
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0
0
0
0
0
o
0
0
0
End View of • •
•
• •
0
Wire Guide
0
0
0 0
0
0
0 0 0
0
Fire 3
0
o
0
0
0
0 0
0 0
0
Solid dots indicate portions
of characters printed by
print wire 3 as the
pri nt head moves
from left to right.
,
--
-
·
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-
·
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- -
-
- - -
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.
~
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•
0
0
0
0
0
Print wires
are numbered
1 through 8,
top to bottom.
-
-
.
I
Fire 4, 5, 6, 7 The character (A)
Theory,
Features
is complete
Theory 5256 MIM 4-25