| 摘要 |
An apparatus and methods for using a Variable Orifice Capillary Wave Printer are disclosed. The invention as described herein provides a capability to transfer high resolution graphical images onto a projection medium (14) with pseudo-gray-scale (i.e. variable spot-size). A standing fluid ripple wave (38) or capillary wave is generated along a narrow channel (20) at the top of an ink reservoir (16), upon the free fluid surface (27). The capillary wave (38) is spatially stablized with an elongated slotted bar (30) of anisotropically etched signal crystal silicon. Piezoelectric pushers (34) are positioned at the anti-nodes (42) of the stabilized standing capillary wave (38) to selectively restrict the narrow slots (32) etched into the slotted silicon bar (30). Selective actuation of one or more piezoelectric pusher (34) for a predetermined length of time results in the ejection of a stream of fluid droplets (12). Pseudo-gray-scale printing is achieved by independently varying the ejction period of each piezoelectric pusher (34). A low-cost, highly integrated and highly producible apparatus (10) may be created by laminating an array of selective transistor switches (36a) and an array of piezoelectric pushers (34) onto a glass substrate (36b) which is embedded in the body of the acoustic ink reservoir (16). The shortcomings of current apparatus designed for selectively addressing the anti-nodes (42) of a stabilized standing capillary wave (38) have been overcome by the Variable Orifice Capillary Wave Printer, making such a device a low-cost and highly producible alternative for the printer industry.
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