Sharp ER-04RP Service Manual page 18

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ER-04RP
'T
Print
In 1
topper
spring
Nose assembly'
\Solenc)id base
(5) Paper feed mechanism
The paper feed mechanism consists of the paper feed power
transmission mechanism described in 2-2-2. (l)-(2), a paper
feed solenoid which controls the clutch mechanism, a PF trigger
lever, and a clutch cam. The PF shaft is driven to feed the paper.
The clutch mechanism has a spring clutch, consisting of a PF
drive gear BK, a clutch gear BK, a clutch spring, and the clutch
cam, to transmit the rotation of the clutch gear BK to the PF
drive gear BK.
Two paper feed methods are available for the printer, the friction
method and the pin wheel method.
PF shaft
,PF shaft gear
PF drive gear BK
v \ '%
eed
d
Drive ge
r lever
PF slip spri
PF
Clutch cam /
\
Clutch spring
Clutch gear BK
@ Friction type (Type D/P61'-'F*)
The friction type consists of two PF rollers fixed to the PF
shaft, pressure rollers press-contracting the respective PF
rollers, and pressure roller springs applying pressure to the
respective pressure rollers. Paper is fed by the friction force
acting between the PF rollers and the pressure rollers. Paper
can be inserted either from the rear or from the bottom.
'Rear
Pressure roller
T
-1
Pressure roller spring
Bottom
(6)
[Paper feed overload protection mechanism]
A safety mechanism is provided to prevent gear breakage
and motor coil burning due to the motor seizure in case
overload is applied to the PF shaft because of paper jam,
etc. The PF slip gear is coupled by friction to the drive gear
via the PF slip spring, and is so constructed that when the PF
shaft is subjected to a greater load than a prescribed torque,
it slips on the PF shaft to absorb the overload.
Side plate R
/
PF
ive
gear
Sll
slip gear
yl
Pivot drive gear
[Paper release mechanism]
Tne PF shaft gear is coupied to the PF ratchet fixed to the
PF shaft so that the ratchet engagement is reieased when
the paper is puiied in the foward direction, thus aliowing the
paper to be srnoothiy puiied out. Aiso, if a knob is mounted
on the PF shaft, the ratchet engagement can be reieased by
puiiing the knob outward, thus aiiowing the PF shaft to be
freeiy rotated. in this situation, the paper can be fed in either
forward or reverse directions by rotating the knob.
—
.Knob
PF
—
PF ratchet
\
.
PF shaft gear
Ribbon mechanism biock
The mechanism biock consists of a ribbon cartridge in which an
endiess ribbon is housed, a ribbon feed gear train, and a ribbon
drive poie SA which is driven by the ribbon feed gear train.
When the motor is in rotation, the ribbon drive poie SA is con-
tinuously rotated via the gear train, to drive the ribbon gear
contained in the ribbon cartridge so that the ribbon is con-
tinuously taken up.
The ribbon drive poie SA is coupied to the ribbon drive gear via
a ratchet, so that it can be rotated freeiy in the direction in which
the ribbon is taken up (in the forward direction). Therefore, the
cartridge knob can be rotated to take up the ribbon with the
ribbon cartridge instailed in the printer.
m
Ribbon drive gear
-16-