摘要 |
Electrorheological based acoustic droplet ejectors and their applications in acoustic print heads are described. The droplet ejectors include an acoustic transducer which generates acoustic energy into a fluid well holding an electrorheological fluid such that the fluid's free surface is adjacent electric field electrodes. The acoustic energy is such that droplets are ejected from the fluid as long as a lower voltage is applied to the electrodes. However, when a higher voltage is applied to the field electrodes, the electrodes produce an electric field through the fluid which causes the viscosity of the fluid to increase sufficiently that droplet ejection is prevented. When used in a print head, the electrorheological fluid is an ink. Further, many (perhaps thousands) of individual droplet ejectors are formed in the print head. By controlling droplet ejection from the individual print heads, an image can be produced on a recording medium.
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