Canon BJC-55 Service Manual

3.2.3 Bubble jet head-unit structurea) Bubble jet nozzlesThe ink in the ink sponge is filtered through a meshed ink filter, and is fed to thebubble-jet nozzles through the ink path in the holder. When the head-drive-currentflows to the heater board of each nozzle, ink is heated up, and bubbles are producedand subsequently form into one large bubble. The head drive current is cut offbefore a drop of ink is ejected from the nozzle, but bubbling continues due to theheat 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 areformed on a silicon plate by means of semiconductor technology.A photosensitive resin layer (nozzle wall) and plastic cover are bonded tothe silicon plate, and nozzles are made in the photosensitive resin layer bylaster.4-23BJC-50Part 4: Technical ReferenceBubble Contraction,Ink Bubble Formation4Ink Drop Jetting5End of Heater Power3While Heater Power is on2Start of Heater Power1Plastic CoverSignal CircuitPrint BoardExtra Fine WireConnecting SectionProtection Bond of WireConnecting SectionSilicon PlateAluminum PlateHeater PlateBubble Jet NozzleCommon Ink ChamberFace Plate (Part of Plastic Cover)Joint PipeInk FilterInk Path from Ink CartrigeFigure 4-16 Bubble Jet Head