Epson Stylus COLOR 3000 Service Manual - Page 51

Operating Principles 2.2.6.1 Pump Mechanism The pump mechanism, composed of the pump motor and pump unit, absorbs viscous ink in the printhead nozzles and drains it to the waste ink drain pad through the cap. Since this printer has only one pump, it uses the pump for both black and color inks by alternating the rotational direction of the pump motor. When the pump motor rotates forward *1 it absorbs black ink. On the other hand, it absorbs color ink with backward rotation *2. The pump unit is composed of the pulley, tube and 2 rollers, as shown in Figure 210. To draw ink, the pulley rotates the rollers which squeeze the tube reducing volume as they move to produce negative pressure. As a result, the ink is vacuumed and drained into the waste ink drain pads by the pressure produced through the operation. *1 The direction in which the paper is fed. *2 The direction in which the paper is fed back. Figure 2-10. Pump Operation Item Motor type Drive voltage Coil resistance Connection Excitation mode Drive frequency Drive current Table 2-6. Pump Motor Specification Description 4-phases / 48-pole / PM type stepping motor 42 VDC ± 5% (The voltage applied to the driver) 7.7 Ω ± 10% (at 25°C per phase) Bipolar 2-2 phase, 1-2 phase, W1-2 phase, Constant current drive 281 to 1250 Hz 825 mA (at fast absorption) 500 mA (at slow absorption) 2-10 Rev. A