Integrated thick film electrostatic writing head

Abstract

An improved electrographic writing head employs interleaved arrays of writing nibs and small geometry, high impedance, thick film resistors and semiconductor driver circuits fabricated on separate glass epoxy substrates disposed in adjacent back to back relation. The writing head achieves significant savings in manufacturing costs by using low cost printed circuit and thick film technology. Power consumption may be reduced by more than half over prior art devices due to the high impedance of each thick film pull up resistor coupled with an associated writing nib. A ground plane is disposed between the adjacent substrates and between adjacent arrays of writing nibs. The ground plane prevents electrical interaction between the substrates and prevents the formation of parasitic nib-to-nib capacitance by shunting parasitic capacitance currents to ground. The ground plane thus reduces the possibility of flaring and substantially eliminates inadvertent writing by adjacent nibs.