Fabrication of integrated nozzle plates for inkjet print head using microinjection process

Abstract

This paper presents a novel concept to fabricate nozzle plates for an inkjet print head using a modified LIGA process. This fabrication technique can reduce the production cost of current nozzle plate. It comprises of a multi-exposure and a single development (MESD) processes, the extra-hard Ni–Co (nickel–cobalt) electroforming and thin-wall plastic microinjection molding. The template of the nozzle plates is patterned using a dry film and MESD processes. Later, the template is transferred into metal Ni–Co mold by electroplating techniques. In this study, the technique of extra-hard Ni–Co alloy electroplating process with Hardness of Vickers over (HV) 550 is developed. Then with this stiffness of Ni–Co mold, it can withstand a high injection speed without deformation. Thin-wall microinjection molding process with a short cycle time to fabricate nozzle plate can be finished. Liquid crystal polymer (LCP) is used for the thin-wall microinjection molding process. Besides, this study presents a novel design of nozzle plates. It integrates of ink channels, cavities and nozzles all in one nozzle plate to reduce the assembly process. The dimensions of nozzle plate are 4.16 mm in width and 7.3 mm in length, respectively. Total thickness of this integrated nozzle plate is 100 μm, whereas the thinnest thickness around a nozzle hole is 40 μm. Nozzle holes with 50 μm in diameter and 169 μm in pitch are suitable for 1200 dpi inkjet print head.