Droplet deposition apparatus

Abstract

An actuator taking the form of a piezoelectric wall separating two chambers, which utilises two actuation modes. Both actuation modes cause volume displacements in both chambers, but act to reinforce one another in one chamber and cancel one another in the other chamber. A fluid pump for droplet deposition having an array of channels separated by such actuators can be operated with each channel acting substantially independently of its neighbours.

Description

technical field [0001] The present invention relates to actuators, and in particular to actuators for droplet deposition devices. Background technique [0002] Droplet deposition devices or inkjet printheads can place small fluidic droplets onto a substrate. This device (hereafter referred to as an inkjet printhead, although the device is also capable of ejecting fluids other than ink) forces the fluid out of nozzles in communication with the ejection chamber. An actuator corresponding to the ejection chamber applies a force to eject the fluid. These actuators take many different forms, but tend to fall into one of two categories. The first of the two categories is mechanical, in which electrical pulses deform the actuator, and the first category includes, for example, techniques such as electrostatic, thermal bending, or piezoelectric. The second category is thermal or bubble actuators, where heat is applied to bring the fluid to its nucleation point. The resulting air ...

AI Technical Summary

Problems solved by technology

However, because each wall acts on both chambers simultaneously, it is impossible to eject droplets from each ejection chamber at the same time, thus reducing the velocity of ejected droplets

Images