Film Ribbon Mechanism - IBM Selectric Manual

FILM RIBBON MECHAN ISM
RIBBON FEED
1 . Ribbon Feed Plate - Posi ti on the feed plate left or right
under its mounting screws to allow the feed pawl to op-
erate front to rear in the guide slot of the feed plate
without binding (Fig. 189).
Feed Plate Feed Pawl
Take-Up Pu Iley
FIGURE 189. Ribbon Feed Plate
CAUTION: Before loosening the right hand mounting
screw remove the drive spring from the take -up pu lIey
so that you will not damage the drive sprillg with your
screwdriver.
NOTE: Ifadditionaladjustmentisnecessary to prevent
the pawl from binding in the slot of the feed plate, the
feed cam follower mounting bracket may be adjusted
left or right under its mounting screws (Fig. 190). If it
is ever necessary to adjust this bracket be sure to main-
tain
.00111
to
.004 11
vertical clearance between the bot ...
tom of the bracket and the carrier support. See Figure
80 in the adjustments of the print mechanism.
'
. . . .
"'-':;~
'-~~~~~~]
Follower Mounting
Bracket
FiGURE 190. Feed Cam Follower Mtg. Brkt.
2.
04
A bind between the feed pawl and the guide slot in the
feed plate wi II cause i ntermi ttent ribbon feed fai lures.
The bi nd prevents the feed pawl from droppi ng into the
next feed window as it is operated to the rear during a
feed operati on.
CAUTION: After changing the position of the feed
plate check the lift control lever to make sure that it
daes not strike the verti ca I lug on the left hand corner
of the feed plate (when the control lever is in its highest
I·r. .'. . _ \
II I I
pU~11101IJ.
Feed Cam Follower Eccentric - Adjust the follower ec-
centri c so that the feed paw I wi II rotate the feed and
lift wheel 1/16 of a turn for each ribbon feed operation
(Fiq. 191).
one Feed
Operati on
FIGURE 191. Feed Cwn Follower Eccentric
This adjustment may be checked in the following manner:
With the machine at rest manually position the feed and
lift wheel so that the steel roller on the lift control
lever rests approximately in the center of a valley (high
lift lobe) on the feed and lift whee I (Fig. 191). Now,
perform a ribbon feed operation by hand-cycling any
character through its complete cyc Ie. Make certain that
the cycle shaft returns to its latched position. If the
follower eccentric is properly adjusted the feed pawl
should rotate the feed and lift wheel 1/16 of a turn
causing the steel roller on the lift control lever to come
torestinthe center of a peak (low lift lobe) on the feed
and lift wheel (Fig. 191).
NOTE: Besuretokeep the high point of the eccentric
up and toward the front when maki ng this adj ustment.
Improper adjustment of the follower eccentri c wi II gen-
erally cause either under or over feeding of the ribbon
plus variations in the ribbon Ii ft pattern. The ribbon
lift operation will only be affected if the feed and lift
wheel fai Is to rotate the proper amount causing the steel
rolleron the lift control lever to fail to reach or remain
on the proper cam lobe of the wheel. This type of fai lure
usually occurs during a low lift operation where the steel
I
uller must come to rest on a peak (low Ii ft lobe) of the
feed and lift wheel.