Printer piezoelectric

There are two types of impulse printers (Eig. 19). A piezoelectric ink jet propels a drop by flexing one or more walls of the firing chamber to decrease rapidly the volume of the firing chamber. This causes a pressure pulse and forces out a drop of ink. The flexing wall is either a piezoelectric crystal or a diaphragm driven by a piezoelectric incorporated into the firing chamber (Eig. 19a). Thermal impulse ink jets also propel one drop at a time, but these use rapid bubble formation to force part of the ink in a firing chamber out the orifice (Eig. 19b). 

The Chemical Inkjet Printer (ChIP), an inkjet printer-like device which is equipped with a piezoelectric reagent-dispensing system, has been developed by Shimadzu Corporation. The ChIP can dispense picoliter volumes of matrix solution onto a tissue section, which has four printing heads and nozzles that have no contact with the tissue section surface. 

An altemahve approach is the "mass-sensing" multianalyte microarray immunoassay first described by researchers at Beckman Coulter, Fullerton, CA (Silzel et al., 1998). As early as 1991, other groups at Beckman Coulter had adapted commercially available ink-jet printers (e.g., the Hewlett Packard Deskjet) for deposihng oligonucleohdes or proteins such as streptavidin onto substrates to create arrays (Matson, xmpublished data). Piezoelectric... 

Ink-jet techniques. Piezoelectric pulsed drop jet devices have been used for target production [26]. These devices are similar to those used in ink-jet printers. 

The microarray manufacturing method that enables microarray printing without direct contact to the surface is termed non-contact printing. Piezoelectric, bubble-generated, and microsolenoid driven pipettes as shown in Fig. 3 work with the same physical principle as ink-jet printers and are capa-... 

Conversely, in a piezoelectric inkjet (PIJ) head, the deflection of a membrane drives ink through each nozzle — schematics of the various configurations used in PIJ heads can be found elsewhere. The timescale for PIJ drop ejection is similar to that in a TIJ head (Fig. 1), thus, both are capable of firing 10000 to 30000 drops from a nozzle each second. Typical nozzle diameters d = 10—50 fxm), ink viscosities ( 7 = 1—5 centipoise), ink surface tensions (a = 20—50dyne/cm), and ink densities (p = 0.9—l.lg/ml) are fairly similar for the TIJ and PIJ printers for office and home use. The resulting key fluidic parameters for such print heads are summarized in Table 2. 

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 many commercially available demand-mode ink-jet systems today, a thin-film resistor is substituted for the piezoelectric transducer. When high current is passed through this resistor, the ink in contact with it is vaporized, forming a bubble over the resistor [17]. This vapor bubble serves the same function as the piezoelectric transducer. This t5rpe of printer is referred to as a thermal ink-jet printer. 

The 3D Systems Thermojet Printer [38] also uses a demand mode piezoelectric array printhead dispensing a thermoplastic material to build solid models. Printing resolutions (actually addressability) of 300, 400, and 600 dot per inch (drop spacings of 85 pm, 63 pm, and 42 pm) are claimed. The maximum model size is 25 cm x 19 cm x 20 cm. 

The micro-droplet piezoelectric ejection system may overcome these obstacles. The device provides collimated flow in a manner similar to ink-jet printers. This facilitates depositing of the drug on the ocular surface and the result differs markedly from eye dropper instillation or spray. 

Figure 25.2 schematically shows the inner structure of an inkjet printer with bend mode [22] piezoelectric DOD technique. Due to the pressure generated by a voltage-pulse driven piezoelectric actuator, liquid is ejected out of small orifices... 

Displacement actuators (converse piezoelectric effect) This class contains various actuators - loudspeakers, camera shutters, buzzers, ink-jet printers, microrobots, relays, pumps, fuel injection systems, and others. 

In the piezoelectric method, a piezoceramic deforms in response to the electronic signal and forces ink out of the orifice. Different manufacturers of these devices utilize different geometries, giving rise to so-called squeeze, bend, push, and shear modes of operation. Squeeze mode print heads are, by now, more a matter of historical interest, and shear mode devices have not yet made a significant commercial impact. Bend and push mode devices, illustrated in Fig. 11, are both commonplace designs in ink-jet printers offered to office, home, and commercial printing markets by a number of manufacturers, including Dataproducts, Epson, Sharp, Tektronix, and Xerox. 

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