A layered heater is provided with a resistive layer having a resistive
circuit pattern, the resistive circuit pattern defining a length and a
thickness, wherein the thickness varies along the length of the resistive
circuit pattern for a variable watt density. The present invention also
provides layered heaters having a resistive circuit pattern with a
variable thickness along with a variable width and/or spacing of the
resistive circuit pattern in order to produce a variable watt density.
Methods are also provided wherein the variable thickness is achieved by
varying a dispensing rate of a conductive ink used to form the resistive
circuit pattern, varying the feed rate of a target surface relative to
the dispensing of the ink, and overwriting a volume of conductive ink on
top of a previously formed trace of the resistive circuit pattern.