Sharp FO-1660 Service Manual page 36

UX-600MU/MC
FO-1660U/C
6. Recording block
(1) General view
Imaging film
Thermal
head
Supply
side
Main frame
Film sensor
lever
6-1. Driving
In the drive mechanism, the rotating force of the pulse motor for both
transmission and reception is transmitted to the paper supply roller,
the recording paper feed roller and imaging film drive gear through
the pulse motor axle gear, reduction gear and planetary gear.
6-2. Recording
This equipment employs the thermal transcription system which used
the thermal head imaging film.
1) Thermal head
The thermal head is composed of 2,016 heating elements in traverse
line, and the resolution power is 8 dots/mm. The maximum speed is
10 ms/line.
2) Structure of recording mechanism
Recording is achieved by applying a suitable pressure to the thermal
head through the imaging film of the recording paper feed roller and
the recording paper.
The main scanning is electronically done, and the sub-scanning is
mechanically done (by sending the recording paper with the recording
paper feed roller).
Platen
roller
Guide shaft
PO guide
PU roller
P-IN sensor lever
Take-up
side
Pinch
roller
Paper guide
PO roller
PE sensor lever
Separate plate
Fig. 7
3) Recording paper transfer sequence
a) The recording paper stored in the RP hopper is fed with the PU
roller, and the recording paper is stopped when the P-IN sensor is
turned on by sensing its lead edge.
b) Hereafter, the imaging film and recording paper are transferred
with the recording paper feed roller, and thermal transcription is
done on the recording paper.
c) After thermal transcription, the imaging film is taken up by the
roller on the take-up side, and the recording paper is discharged
by the PO roller.
As basic, the density unevenness mainly results from the longitu-
dinal misalignment of the thermal head to the heater line. Other-
wise, the head is in uneven contact with the recording paper feed
roller, or the imaging film is wrinkled.
The following items are described as the simplified checking
1 method.
Are the power and signal cables of the thermal head suitably
treated?
2
Does the same symptom appear even if the thermal head pres-
3 sure spring is replaced?
Is the feed roller of the recording paper concentric? (Density is
uneven at intervals.)
4
Does the same symptom appear even if the thermal head is re-
5 placed?
Is the imaging film stained or wrinkled?
3 – 3
RP hopper
Rotation plate