HP Designjet 5000 Service Manual - Page 384

Functional Overview Air Pressurization System (APS) The APS is the system that provides and controls the pressurization of the ink in the Ink Cartridges and is located under the ISS. The key purpose of this system is to ensure the minimum required ink pressure at the inlet to each Printhead respectively at the required print rates. The APS is also used to provide pressure for tube purge and as part of the blow prime system operation. Air Tube to Air Connector and Ink Cartridges Cables to ISS PCA DC motor-driven air pump Analog pressure sensor Two-way solenoid valve The APS pressurizes the ink in the Ink Cartridge bags by pressurizing the air around them. The Printer controls the air pressure using the pump with feedback from the sensor; when required the valve is opened to depressurize the air circuit. This allows control of the ink pressure at the inlet to the Printheads. Leak Detect System (LDS) The purpose of the Leak Detect System (LDS) is to detect the breakage of any of the Tubes that deliver ink from the Ink Cartridges to the Printheads. If a Tube breaks, as the system is pressurized, the ink flows through the breakage and gets between the Tube and the Tube Carrier, and is forced to go to the Ink Leak Detector where the leaking ink is collected. There will be a potential short circuit between the two metallic pins, and the ink leak will be detected. 10-8 HP DesignJet 5000 Series Printers Service Manual