Canon BJC 50 Service Manual - Page 111

BJC-50 3.2.3 Bubble jet head-unit structure Part 4: Technical Reference a) Bubble jet nozzles The ink in the ink sponge is filtered through a meshed ink filter, and is fed to the bubble-jet nozzles through the ink path in the holder. When the head-drive-current flows to the heater board of each nozzle, ink is heated up, and bubbles are produced and subsequently form into one large bubble. The head drive current is cut off before a drop of ink is ejected from the nozzle, but bubbling continues due to the heat remaining in the heater and the drop of ink is ejected from the nozzle. After ejecting the ink drop, the nozzle is refilled with ink. The heaters and their electrical elements within the bubble jet head are formed on a silicon plate by means of semiconductor technology. A photosensitive resin layer (nozzle wall) and plastic cover are bonded to the silicon plate, and nozzles are made in the photosensitive resin layer by laster. Extra Fine Wire Connecting Section Protection Bond of Wire Connecting Section Silicon Plate Aluminum Plate Heater Plate Bubble Jet Nozzle 1 Start of Heater Power 2 While Heater Power is on 3 End of Heater Power 4 Bubble Contraction, Signal Circuit Print Board Ink Path from Ink Cartrige Ink Filter Joint Pipe Plastic Cover Common Ink Chamber Ink Bubble Formation 5 Ink Drop Jetting Face Plate (Part of Plastic Cover) Figure 4-16 Bubble Jet Head 4-23