Epson Stylus Pro 3800 - Page 42

Epson Stylus Pro 3800/3800C/3850/3880/3885/3890 Revision C
OPERATING PRINCIPLES Ink Supply Mechanism 42
2.3.2.1 Pressure Pump Unit Mechanism
 Accordion unit/Pressure pump motor/Pressure pump home sensor
The accordion unit intakes air and applies pressure by the rotating drive of the pressure
pump motor, and pumps air into the ink cartridges. The pressure pump home sensor
detects the position of the accordion unit.
Figure 2-7. Drive Transmission Path
 Pressure sensor unit
A reflective photo sensor, which turns on when the air pressure reaches the
predetermined level, controls the amount of pressure. When the air pressure reaches
the predetermined level, film on the air damper expands and activates the reflective
plate causing the sensor to receive light, and the pressurizing state is detected.
 Regulator
Stops applying pressure when the power is off or during stand-by. Activated by the
pressure pump motor through the clutch. The regulator opens the valve to reduce
pressure.
Figure 2-8. Pressure Pump Unit
Combination Gear, 18, 39
Clutch
Spur Gear, 24.5
Spur Gear, 22
Regulator
Pressure pump motor
Accordion Unit
Reducing
pressure
Applying
pressure
CW rotation CCW rotation
Clutch
Spur Gear, 22
Spur Gear, 24.5
Accordion Unit
Pressure
Pump Motor
Valve
Clutch
Applying pressure
CW rotation of the
clutch closes the valve
and applies pressure to
send air toward the ink
cartridges.
Reducing pressure
CCW rotation of the clutch opens
the valve and reduces pressure.
When the air pressure reaches
the predetermined level, the
valve opens as the pressure
overcomes the tension of the
spring that presses the valve.
Combination Gear 18, 3.9
Regulator
Pressure Sensor Unit
Sensor
Pressure Pump
Home Sensor
Air Damper Film