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 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.

Pulley

Ink Drawing

Ink Draining

Ink Draining

Ink Drawing

Pump Motor (Backward):Color Ink Drawing

Pump Motor (Forward):Black Ink Drawing

Pulley

 

No Ink Drawing

 

 

No Ink Draining

No Ink Draining

No Ink Drawing

 

Pump Motor (Backward):No Black Ink Drawing

Pump Motor (Forward):No Color Ink Drawing

 

Figure 2-10. Pump Operation

 

Table 2-6. Pump Motor Specification

 

 

ItemDescription

 

 

 

 

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)

 

2-10

Rev. A