Sharp FO-1470 Service Manual page 35

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 me
chanically done (by sending the recording paper with the recording pa-
per feed roller).
Platen
roller
Guide shaft
U turn guide
PU roller
P-IN sensor lever
Take-up
side
Pinch
roller
Paper guide
PO roller
Rotation plate
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.
1 The following items are described as the simplified checking 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-sure
spring is replaced?
3
Is the feed roller of the recording paper concentric? (Density is un-
even at intervals.)
4
Does the same symptom appear even if the thermal head is replaced?
5
Is the imaging film stained or wrinkled?
3 – 3
UX-510UA
FO-1470U
RP hopper