Inkjet printhead substrate with distributed heater elements

A substrate heater for an inkjet printhead having a plurality of ink jet nozzle structures, comprising:

• a plurality of series-connected substrate heating resistors forming a string, one end of said string connected to a supply voltage;
• each said resistor connected to a neighbor resistor by a low resistance conductor;
• at least one switching transistor connected to a different end of the resistor string;
• and
• each resistor of said resistor string located thermally adjacent at least one respective nozzle structure, whereby the number of nozzle structures equal or exceed the number of substrate heating resistors.

A substrate heater for an inkjet printhead having a plurality of ink jet nozzle structures, comprising:

• a plurality of series-connected polysilicon substrate heating resistors, each said polysilicon heating resistor connected to a neighbor polysilicon heating resistor with a metal interconnection;
• a plurality of parallel-connected FET switching transistors, a respective drain connection of said parallel-connected FET switching transistors connected to said series-connected polysilicon substrate resistors for controlling heating current therethrough;
• a gate of each said parallel-connected FET switching transistor connected in common and driven by a common drive signal;
• and
• one said polysilicon resistor and a pair of said FET switching transistors forming a group, and wherein at least one said nozzle structure is located thermally adjacent a polysilicon heating resistor of one said group.