Cr Motor Driver Circuit - Epson DFX-5000+ Service Manual

Operating Principles
11. Head temperature sensor (uses a thermistor)
12. Fan temperature sensor (uses a thermistor)
13. Paper width sensor
14. Carriage motor isolation resistance sensor (monitored by port AN0 ofthe
CPU)
To provide information about the carriage motor life, the analog port (ANO) of
t h e
CPU checks the isolation resistance every time the printer is turned on. Ifthe
isolation resistance is less than 1 KR, a carriage error is detected and the printer
beeps. (Refer to Buzzer Operation, in Chapter 1 ofthis manual.)

CR Motor Driver Circuit

Figure 2-22 shows the internal circuit for the CR motor, and Figure 2-23 shows a
block diagram for the CR motor driver circuit. An SLA5007 bipolar driver IC
drives the CR motor. It has built-in bipolar switching transistors and a current
limiter. A comparator IC (NJM 2903) monitors the current in the CR motor driver
IC (SLA5007). Ifthe current exceeds the set value, it is fed back to the gate array
transistors (Q4, Q7, and QS).
When the printer is turned on, CPU analog port AN0 measures the isolation
resistance in the CR motor at once. Ifthe isolation resistance is less than 1 KR:
the CPU sounds the buzzer.
ENCA ofthe gate array, and the ENCB pulse that the carriage encoder outputs
is input to general purpose port ENCB ofthe gate array. The gate array counts
these pulses using the internal counter and determines the amount and direction
of motor rotation.
Table 2-4 lists the CR motor drive modes. The printer has three deceleration
control modes. The degree of deceleration is determined by how the carriage motor
transistors are driven. Table 2-5 describes how the transistors are driven for each
mode.
2-30
Pulled up to 3.32 KR resistance
CR filter circuit (1 KR and 0.1 pF)
Pulled up to 3.32 KR resistance
CR filter circuit (1 KR and 0.1 pF)
Emitter follower
CR filter circuit (10 KR and 0.01 pF)
No paper present: Standard voltage level.
Paper present: The voltage level is double the standard voltage level.
EPSON DFX-5000+ Service Manual