Precision X-Y stages were developed for integration into a new analytical measurement tool for use in the development of digital inks or other fluids to be jetted from ink jet print heads. The Drop Watcher III system provides repeatable and exact measurements of drop formation (e.g., distance and time from the start of the drop ejection), drop size, and flight characteristics of opaque or transparent fluid drops. In addition to X-Y stages, the system consists of a monochrome CCD camera with a zoom lens providing magnification from 0.75X to 4X. Magnification from 2.5X to 10X is achievable when using the high-magnification option, yielding fields of view from 640 µm to 2.56 mm.
Powered by a five-phase stepper motor, the X-Y stages perform precise measurements of the fluid-jetting parameters of ink jet print heads by moving the camera through micrometer adjustments across the entire print head. This allows the user to automatically track individual drops of ink (or other jet-able fluids) at various stages of formation across all nozzles in a print head. When combined with micro-stepping controllers, the motor can also provide submicron step sizes. Typically, drop volumes can range from 3 to 150 picoliters, depending on the print head nozzle size and drive waveform used to drive the print head. The X-Y platforms of the analytical tool are configured to automatically run all measurements over a user-specified number of nozzles.
To minimize flexing and twisting, the stages utilize a Ushaped outer rail and parallel rows of ball bearings, providing a very rigid platform for accurately moving high loads. This bearing arrangement also allows flexibility in mounting the stage. It has the same load capacity upside down or on its side as it has in the normal, upright orientation. Designed for long life, the stages include a grease fitting to allow the bearings to be lubricated without any disassembly.