43471801TH Rev.1
11 /
Oki Data CONFIDENTIAL
2.2.5 Spacing
The LSI (MG74Q514-131) outputs space motor phase signals (SP_PHA,SP_PHB) when it receives a
spacing command from
µ
CPU. It outputs IPT signals as the dot timing and carriage position detection
timing in sync with these phase signals.
The space motor phase signals (SP_PHA,SP_PHB) are input to the motor driver, which drives the space
motor.
2.2.6 Line feed
The LF motor phase signals (LF_PHA, LF_PHB) from LSI (MG74Q514-131) are input to the motor driver,
which drives the LF motor.
2.2.7 Alarm circuit
(1)
High-temperature head alarm
The temperature of the head is monitored by a thermistor embedded in the head to protect the
head coil.
The head temperature will rise after continuous heavy-duty print jobs. Therefore, when the
head rises beyond a specified temperature, a thermal alarm mode will be entered, and after the
current line is printed, the speed for printing the following lines will be decreased. Furthermore,
if the head temperature does not fall, the following lines will be divided into two depending on
the temperature, and printed by single-direction print.
The alarm is detected when the resistance of the thermistor decreases from the rise in the
head temperature and CPU is input in the A/D converter.
2.2.8 Paper-end detect circuit
When paper runs out, the photosensor (PE) goes Hight level and the paper-end signal becomes
1
. This
signal is input in CPU which goes on the B lamp.
2.2.9 Power source unit
The power source unit supplies DC+35V and +5V to each section by switching power.
SH_PHA
SP_PHB
Motor driver input
LF_PHA
LF_PHB
Motor driver input
