New Print Head Technology for High Productivity and Stability

Abstract

SII Printek produces printheads characterized by their high productivity. Our ink-jet printheads realized such high productivity with edge shooter structure operating in shear mode until now. Most especially, 508GS model has been popular covering a wide range of ink chemistry and capable of jetting at a high frequency thanks to its isolated channel structure. However, even higher stability at high production rate is demanded in any industrial market, particularly those prints in single pass. Hence we developed a new product which adopted the following techniques to cope with such demands.Firstly, we adopted side shooter structure where a nozzle is located in the center of pressure chamber with openings at both ends to enable ink circulation across. Thereby we can save a large quantity of ink consumption wasted for filling of ink and cleaning of nozzle. Continual ink flow beside the nozzle realizes self-recovery of meniscus as well.Secondly, we adopted our isolated channel structure where discharging and non-discharging channels are alternately grooved and only the latter are actively driven.In this way, electrodes of discharging channels immersed in ink are free from any corrosion and active channels can operate at a high frequency since they are isolated from each other and hence free from crosstalk.Thirdly, we adopted a cantilever structure where the channel walls of the actuator are held rigidly by stiff material at one end and flexibly at the other, from which electrodes extend covering about half height of the wall. This allows us to effectively drive the discharging channel without too much modifying the simple conventional process. Incorporating these three structures together allows us to jet a large volume of drop at a high frequency, but such a large ink flow digitally driven causes big pressure shock occurring at onset and end of a print streak, starving and over-pressuring the printhead in turn. We introduced a dumping structure to supress such a big shock affecting the actuator operation. Thus we could achieve good printing sustainability that can endure any pressure fluctuation, not only due to sudden change in pinting streak but also from outside disturbance. In conclusion, our new inkjet printhead RC512 realized very high productivity and sustainability for industrial printing.Its productivity exceeds our existing product lineup by far, and we are amazed to see a stable discharge is possible with such productivity. We are further developing a new model evolved in the line of this structure aiming at even higher performance.