Inkjet printhead with nozzle layer defining etchant holes

#The present invention relates to ink jet printing. In particular, the invention relates to an inkjet printhead chip with predetermined micro-electromechanical systems height.

#Many different types of printing have been invented, a large number of which are presently in use. Known forms of printers have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.

#In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles, has become increasingly popular primarily due to its inexpensive and versatile nature.

#Notwithstanding any other forms, which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

#FIGS. 1-3 illustrate basic operation of the preferred embodiments of nozzle arrangements of a printhead chip of the invention.

#FIG. 4 is a sectional view of one embodiment of a nozzle arrangement of a printhead chip of the invention.

#In the preferred embodiments of the invention, a drop on demand ink jet nozzle arrangement is provided which allows for the ejection of ink on demand by means of a thermal actuator which operates to eject the ink from a nozzle chamber. The nozzle chamber is formed directly over an ink supply channel thereby allowing for an extremely compact form of nozzle arrangement. The extremely compact form of nozzle arrangement allows for minimal area to be taken up by a printing mechanism thereby resulting in improved economics of fabrication.

#Turning initially to FIGS. 1-3, the operation of the preferred embodiment of the nozzle arrangement is now described. In FIG. 1, there is illustrated a sectional view of two ink jet nozzle arrangements 10, 11 which are formed on a silicon wafer 12 which includes a series of through-wafer ink supply channels 13.

#Located over a portion of the wafer 12 and over the ink supply channel 13 is a thermal actuator 14, which is actuated so as to eject ink from a corresponding nozzle chamber. The actuator 14 is placed substantially over the ink supply channel 13 as a cantilever (see FIGS. 1-3). In the quiescent position, the ink fills the nozzle chamber and an ink meniscus 15 forms across an ink ejection port 35 of the chamber.