Patent ID: 6227640
Filing Date: 2001-05-08
Classification: B41J,Y10T

Abstract:
An inkjet printing apparatus for generating a variable mass drop comprising:a planar heater resistor having a shape of a first geometric figure with a perimeter and disposed on and having a first surface in contact with a substrate;a first electrical conductor coupled to said planar heater resistor and a second electrical conductor coupled to said planar heater resistor, whereby an electrical voltage applied between said first electrical conductor and said second electrical conductor produces heat energy in and dissipated by said planar heater resistor; anda protection layer disposed at least on a second surface of said planar heater resistor, said protection layer having a first thickness disposed in the shape of a second geometric figure at a predetermined location entirely within a boundary in said protection layer congruent with said perimeter and a second thickness surrounding said first thickness, said second thickness having a greater magnitude than said first thickness to provide said protection layer with a surface that stably nucleates vapor bubbles at least at two energy levels.