A Non-Contact High-Speed Inspection System for Ink Jet Print Head Nozzles

Abstract

Ink jet nozzle plate production includes inspection of each nozzle for morphological defects such as nicks, cuts, or blockages. Defective nozzles will result in compromised print quality. Once nozzle plates are integrated into the print head assembly, print testing can be used to verify head performance. However, inspection of the nozzles themselves earlier in the production process will decrease the number of print head failures. 100% inspection of nozzle plates is time consuming and it requires specialized inspection equipment and processes, but is the only guarantee of part quality.Inspection of ink jet print head nozzles requires high-speed, automated processes to support production volumes. Challenges such as illumination, depth of focus, part orientation, and image capture speed have resulted in falsely inflated part rejection rates when traditional inspection systems are used. To minimize false rejection rates and to minimize the amount of operator intervention required for manual inspection, a more robust inspection system is needed.This paper will present a novel inspection approach using existing image analysis technology for quantifying nozzle morphology integrated with sophisticated multi-axis motion control, automatic positioning adjustment, and a line scan camera for acquisition of single, non-stitched images.