Paper Feed Motor Drive Circuit - Epson DFX-8500 Service Manual

DFX-8500

PAPER FEED MOTOR DRIVE CIRCUIT

Stepping motor driver STK6713BMK4 (IC2) drives the paper feed motor. Figure 2-22 shows the paper feed
motor drive circuit block diagram, and Table 2-9 contains motor specifications.
Specification
Form
Supply Voltage
Internal Coil Resistance
Frequency
Current Consumption
The motor pulse switching signals are transmitted from CPU ports PG00 to PG03. The paper feed motor is
controlled using open-loop phase switching based on the specified time data. The phase driving method is
1-2 phase excitation. (When the paper feed motor is held, the phase driving method is 1-phase excitation.)
The CPU determines the paper length and whether the pull tractor is installed, then selects the most suitable
driving mode from the modes below.


Micro feed (adjust) mode: < 20 / 432 inches


Middle speed mode:


Normal speed mode:
Each phase switching FET in driver IC2 is an open collector. When the phase switching data is HIGH, the
motor is turned on. The PFA port of the gate array monitors the phase A signal of the paper feed motor and
checks whether it is operating normally. The PFA port is used as the WDT (watch dog timer).
If paper feed motor operation is abnormal, the gate array outputs the /RSTOUT (reset request) signal to the
system reset IC (IC13). See "Reset Circuit" on page 2-21.
2-32
Table 2-9. Paper Feed Motor Specifications
Description
4-phase, 200-pole, hybrid pulse motor
+37 VDC (applied to the drive circuit)
2.8 Ω +10% per phase at 25
Normal mode, constant driving:
4274 pulses per second (pps), 9.9 inches per second (ips)
Middle speed mode, constant driving:
2610 pps, 6 ips
Driving: 1.75 A, + 0.20 A per phase (average)
Holding: 0.26 A, + 0.20 A per phase (average)
> 20 / 432 inches and < 60 / 432 inches, or with optional pull tractor
> 60 / 432 inches
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