US 4,399,348 A · Thermal print head and method of fabrication

Abstract

A high resolution thermal print head and method of fabrication is provided in which resistive elements are located at the edge of a dielectric support which functions as a spacer and is sandwiched between opposing substrates which carry vertically running electrodes on their inner faces. The electrodes extend to the edge of the spacer where they make electrical contact with opposing sides of the resistive elements. In one embodiment, the resistive elements are recessed into the edge of the spacer to minimize wear. The edge-on contact provided by the print head with the printing paper provides that all the supporting circuitry is orthogonal to the plane of the paper. In one embodiment, the spacer is provided with channels for coolant which is circulated immediately beneath the resistive elements. In another embodiment, the writing surface of the print head is ground down over opposing electrodes to expose the tops of the electrodes and to provide channels at the positions where resistive elements are to be placed, with resistive material deposited in the channels and then ground off to the desired head configuration. Only that portion of a resistive material lying between the exposed opposing electrodes is heated upon the application of power to the electrodes.

Claims14

Dependent claims

A thermal print head comprising:

a pair of opposing substrates having top edges in one plane and a dielectric spacer sandwiched therebetween to produce a sandwiched structure extended in one direction, said dielectric spacer having recesses at the edge associated with the top edges of said opposed substrates;
resistive material located within said recesses to a level flush with the top edges of said opposing substrates thereby to form recessed thermal print elements;
means for applying power to selected thermal print elements;
and
wherein said spacer includes at least one channel running beneath said recesses, and further including means for flowing fluid through said channel for the cooling of said thermal print elements.

2 more elements

A print head for a thermal printer, comprising:

a planar dielectic support member having a support member edge provided with a plurality of transversely extending recesses formed therealong at spaced-apart points;
a resistive material disposed in individual ones of said spaced-apart transversely extending recesses for providing a like plurality of resistive print head elements;
a first planar substrate having first and second surfaces and a first substrate edge;
a first metalization pattern disposed on said first surface of said first substrate for providing a like plurality of spaced-apart conductive paths each terminating at spaced-apart points at least proximate said first substrate edge;
a second planar substrate having third and fourth surfaces and a second substrate edge;
a second metalization pattern disposed on said third surface of said second substrate for providing a like plurality of spaced-apart conductive paths each terminating at spaced-apart points at least proximate said second substrate edge;
means for supporting said planar dielectric support member between and abutting said first and said second substrates such that confronting ones of said conductive paths on said first and said third surfaces of said first and said second substrates are electrically connected to a corresponding one of said resistive print head elements provided in said recesses of said dielectric support member;
and
means coupled to said second and said fourth surfaces of said first and said second substrates for providing external electrical connection to corresponding ones of said conductive paths respectively on said first and said third surfaces of said first and said second substrates.

6 more elements

Dependencies are inferred from the claim text.

Thermal print head and method of fabrication

Life of this patent

Thermal print head and method of fabrication

Life of this patent

Abstract

Claims14