Epson Stylus Color 1520 Service Manual page 56

Operating Principles
The pump mechanism absorbs ink inside the printhead and drains ink to the waste ink drain pads via the
cap. Since the printer has black and color printheads, the pump mechanism functions for the both by using
the alternating directions of the PF motor. When the PF motor rotates forward (the direction for feeding
paper), the pump is used for the black printhead. When the PF motor rotates backward (the direction for
feeding back paper) the pump is used for the color printhead. The pump mechanism is composed of 2
rollers, a tube, and a pulley. To draw ink, the pulley rotates the rollers, squeezing the tube to produce
negative pressure, absorbing the ink and draining it to the waste ink drain pad.
Pulley
Ink Drawing
Ink Draining
Ink Draining
Ink Drawing
PF Motor (Forward): Black Ink Drawing
PF Motor (Backward): Color Ink Drawing
Pulley
No Ink Drawing
No Ink Draining
No Ink Draining
No Ink Drawing
PF Motor (Backward): No Black Ink Drawing
PF Motor (Forward): No Color Ink Drawing
Figure 2-14. Pump Operation
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