Epson SQ-B50/2550 Technical Manual page 92

REV.-A
2.4 CONTROL CIRCUIT AND PRINTER MECHANISM OPERATION
This section explains in detail the operation theory of the various parts of thecontrol circuit and printer
mechanism.
2.4.1 Operation of the Paper Feed Mechanism
The operation of the paper feed mechanism, the drive circuit and control circuit are explained here.
The paper feed mechanism contains the following
parts.
• Paper feed mechanism that drives the platen and tractor.
• TE holder mechanism
• PE sensor and TE sensor
• Paper change mechanism (friction tractor)
• CSF sensor
2.4.1.1 Paper feed mechanism
The paper feed mechanism is driven by the paper feed motor. The paper feed motor is a 4-phase
stepping motor capable of bi-directional rotation, rotation in arbitrary amounts, and stopping. Motor
power is transferred by the paper feed change mechanism to the platen (friction) and to the pull tractor
unit (tractor). Specifications for the paper feed motor are shown below.
Type:
Drive voltage:
Coil resistance:
Drive method:
Consumption current:
Drive time:
Hold time:
Drive frecuency:
Minimum feed pitch:
4-phase, 96-pole PM type pulse motor.
24VDC
±
10% (applied voltage to driver)
2.7 ±O. 4ohm/phase (at 25oC)
2-2 phase excitation. Constant-current control.
Acceleration control time
1.0A/phase
±
10%
(Maximum chopping current, minimum average value).
Speed reduction, constant-speed control time
0.74A/phase
±
10%
0.04A/phase ±O.O 1A/phase (DC ammeter average current value)
1440 pps (4.00 IPS)
950 pps (2.64 IPS)
800 pps (2.22 IPS)
500 pps (1.39 IPS)
340 pps (0.94 IPS)
1/360" (approx. 0.07mm)/1 step
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