In 1982, Robert Howard came up with the idea to produce a small color printing system that used piezos to spit drops of ink. He formed the company, R.H. (Robert Howard) Research (named Howtek, Inc. in Feb 1984), and developed the revolutionary technology that led to the Pixelmaster color printer with solid ink using Thermojet technology. This technology consists of a tubular single nozzle acoustical wave drop generator invented originally by Steven Zoltan in 1972 with a glass nozzle and improved by the Howtek inkjet engineer in 1984 with a Tefzel molded nozzle to remove unwanted fluid frequencies. This technology requires the Drop-On-Demand (DOD) inkjet to operate above the piezo Curie temperature for 'preload' tension on the fluid chamber. The piezo must be forward biased to maintain molecular alignment and proper physical state. There are six physical states for piezos: unpoled (forward and reversed biased), positive poling (forward and reversed biased), and negative poling (forward and reversed biased). Howtek Thermojet uses positive poling with forward biased voltage that is removed and applied to produce a fluid "fill" before "firing" a drop. Each drop requires only one fill/fire pulse and no additional drops should be expelled if designed correctly.