Pump Mechanism - Epson STYLUS 3000 Service Manual

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 *
2
backward rotation * . 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
Motor type
Drive voltage
Coil resistance
Connection
Excitation mode
Drive frequency
Drive current
2-10
1
it absorbs black ink. On the other hand, it absorbs color ink with
Figure 2-10. Pump Operation
Table 2-6. Pump Motor Specification
4-phases / 48-pole / PM type stepping motor
42 VDC 5% (The voltage applied to the driver)
7.7 ± 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)
Description
Rev. A