Continuous Inkjet Printing
Eastman Kodak Company, US
Keywords: Inkjet Pringing, MEMS drop ejector, electrostatic drop ejection, squeeze film analysis, drop on demand
Abstract:Microfluidic devices are finding increasing use in a broad range of applications that benefit from high-speed and low-cost patterned deposition of discrete samples (droplets) of micro- or nanoscale materials. A wide range of materials can be jetted using modern microfluidic devices including liquid metals, dispersions of nanoparticles, electrical, and optical polymers, myriad biomaterials, sealants and adhesives. Emerging applications in this field include printing functional materials for flexible electronics, printing biomaterials, and 3D rapid prototyping. The most commercially successful applications involve traditional inkjet printing wherein streams of picoliter-sized drops are ejected at high repetition rates onto a media to render an image. Inkjet printing can be broadly divided into drop-on-demand (DOD) printing, and continuous inkjet (CIJ) printing. In DOD printing, droplets are produced as needed to form an image, whereas in CIJ printing droplets are produced continuously, but only a fraction of these are used to form the image. The unused droplets are deflected from the printing path and recycled. In this presentation we will provide an overview of continuous inkjet technology and applications. We will discuss conventional CIJ systems that utilize piezoelectric-driven droplet generation and electrostatic droplet deflection. We will also discuss a novel CMOS/MEMS-based CIJ technology in which thermocapillary modulation is used to generate variable-sized droplets at each orifice of a printhead manifold. The topics covered will include a comparison of DOD and CIJ operation, a description of microfluidic CIJ devices, device physics, modeling and applications.