Design of a high-density thermal inkjet using heat transfer from CVD diamond

Abstract

A novel high-density thermal inkjet (TIJ) was proposed to overcome the defect due to the limitations of the nozzle density in conventional TIJs, and its feasibility was verified by a bubble visualization test. To develop the high-density TIJ, two concepts were introduced. One is an original method to use heat transfer from CVD diamond by means of placing heaters on the sidewall of the ink inlet in order to minimize the area that is occupied by the heaters. The other is the concept of placing some parts concerning the flow of ink (e.g. manifold, inlet, pressure chamber and nozzle) in line. In order to determine the dimensions of the suggested model, heat transfer analysis has been performed and shapes of the heater based on the analysis have been described. To demonstrate the feasibility of these concepts, the TIJ was designed and fabricated for the bubble visualization test. The CVD diamond on the sidewall was deposited using hot filament CVD (HFCVD). The bubble generated has a better symmetry as the power applied increases, which confirms the possibility of bubble formation by heat transfer from diamond. In addition, there was a difference in the rate of bubble growth between the top and the bottom of the CVD diamond.