Piezoelectric Drop-on-Demand

J. Roeraade, Nanoliter Titration Based on Piezoelectric Drop-on-Demand Technology and Laser-Induced Fluorescence Detection, Anal. Chem. 1998,... 

Several types of fluids may be jetted via inkjet heads, which can be of the continuous inkjet variety (CIJ, primarily aqueous or solvent-based), thermal inkjet (TIJ, primarily aqueous, but some solvent and UV/aqueous hybrids exist), or piezoelectric drop-on-demand (DOD, aqueous, solvent, oil, UV curable). While there are advantages and disadvantages for each type of hardware and fluid, a clear leader in growth has emerged from the list. UV curable inkjet... 

Droplet generator Piezoelectric drop on demand Piezoelectric ink jet Piezoelectric micro-/ nanoliter droplet dispenser... 

UV curable, inkjet, industrial, graphic arts, digital, piezoelectric, drop on demand... 

As seen in Figure 5.1, there are two main types of drop-on-demand technologies. The thermal ink jet or bubble jet has a heating element that causes a vapor bubble to eject an ink droplet from the nozzle. The piezo ink jet uses a piezoelectric transducer for ejecting ink droplets. The microjet technology is a further... 

Biehl et al. demonstrated a method to fabricate microlenses from hybrid organic-inorganic materials on glass using drop-on-demand inkjet printing with 50 /xm nozzles driven by piezoelectric... 

Derived from standard desktop printers, drop-on-demand techniques, such as electrohydrodynamic jet (e-jet) printing, solid freeform fabrication (SFF), or piezoelectric inkjet printing, are among a few notable examples of rapid prototyping techniques that have been developed to pattern biomaterials. With the incorporation of a user friendly computer interface, these techniques have been employed to process a number of multiplexed, biomaterial constructs without the use of masks, stamps, or any other time consuming processing equipment. The design of such constructs with minimal feature sizes in the microliter to picoliter resolution has been demonstrated and will be discussed below. 

In the 1950s, Hansell observed the production of drops by electro-mechanically induced pressure waves [8]. In this type of system, a voltage pulse applied to a piezoelectric material that is directly or indirectly coupled to the fluid, at ambient pressure, induces a volumetric change in the fluid. This volumetric change creates pressure/velocity transients within the fluid that are directed so as to produce a drop from an orifice [9-11]. Since the voltage is applied only when the drop is needed, these types of systems are called drop-on-demand or demand mode. ... 

Abstract This chapter provides information on different types of drop-on-demand drop generators. It starts with thermal or bubble jets, in which a nucleation bubble is used to eject a droplet out of an orifice. This is followed by piezoelectric, pneumatic, microfluidic, electrohydrodynamics (EHD) and aerodynamic droplet generators. For each droplet generator, the principle of operation and major features and characteristics are described. 

Piezoelectric Actuation in Multiphase Microfluidics, Fig. 1 (a) Schematics of a microfluidic chip for drop-on-demand dispensing. The bottom chamber is filled with an aqueous reagent A piezoelectric bimorph actuator glued to the chamber allows the release of an aqueous drop on demand in the horizontal channel filled with an immiscible fiuid. (b) Description of the experimental setup. The... 

One t) e of drop-on-demand system is a piezoelectric device that has as its major components an ink-fitled channel or passageway having a nozzle on one end and a piezoelectric transducer near the other end to produce pressure pulses. 

FIGURE 11 Two geometries of piezoelectric driven drop-on-demand print heads bend-mode (top) and push-mode (bottom). (From Le, H. R (1998). J. Imaging Sci. Technol. 42,49-62 by permission of the copyright holder, the Society for Imaging Science and Technology.]... 

One of the most attractive precision dispensing methods for low-viscosity adhesives is the use of microjet printing technology.10 This technology is based on piezoelectric demand mode ink-jet printing, which can produce droplets of polymeric resins 25 to 125 flin in diameter, at rates up to 1000 drops per second. 

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