Epson Stylus COLOR 3000, Service Manual, Page: 51 / 180

Operating Principles
Rev. A
2-10
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 2-
10. 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.
Item Description
Motor type 4-phases / 48-pole / PM type stepping motor
Drive voltage
42 VDC
±
5% (The voltage applied to the driver)
Coil resistance
7.7
Ω
± 10% (at 25°C per phase)
Connection Bipolar
Excitation mode
2-2 phase, 1-2 phase, W1-2 phase,
Constant current drive
Drive frequency 281 to 1250 Hz
Drive current
825 mA (at fast absorption)
500 mA (at slow absorption)
Pulley
Ink Draining
Ink Drawing
Pump Motor (Backward):Color Ink Drawing
Pump Motor (Forward):Black Ink Drawing
Ink Draining
Ink Drawing
Pulley
No Ink Draining
No Ink Drawing
No Ink Draining
No Ink Drawing
Pump Motor (Forward):No Color Ink Drawing Pump Motor (Backward):No Black Ink Drawing
Figure 2-10. Pump Operation
Table 2-6. Pump Motor Specification