Epson 3800 Service Manual - Page 42

EPSON Stylus Pro 3800/3800C/3850 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. Pressure pump motor Combination Gear, 18, 39 CW rotation CCW rotation Applying pressure Spur Gear, 24.5 Reducing pressure Spur Gear, 22 Accordion Unit Clutch Regulator 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. Applying pressure CW rotation of the clutch closes the valve and applies pressure to send air toward the ink cartridges. Valve 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. Pressure Pump Home Sensor Spur Gear, 24.5 Accordion Unit Sensor Revision A Clutch Combination Gear 18, 3.9 Clutch Regulator Spur Gear, 22 Pressure Pump Motor OPERATING PRINCIPLES Air Damper Film Pressure Sensor Unit Figure 2-8. Pressure Pump Unit Ink Supply Mechanism 42