Thermal printing head

A thermal printing head comprising:

• a substrate formed of an electrical insulator;
• heating elements formed on said substrate;
• conductive layers each formed on the part of the surface of each of said heating elements that is adjacent to and on either side of a heat generating portion of the heating element;
• and protective layers each formed on the surfaces of each of said conductive layers and said heat generating portion of each of said heat generating elements,
• the heating elements comprising a composite of an intermetallic compound and an electrically insulating material,
• the resistivity of said heating elements being not less than 10000 .mu..OMEGA..multidot.cm, and the thickness of said conductive layers at least in the vicinity of the heat generating portions of said thermal printing head being not more than 300 nm.

A thermal printing head comprising:

• a substrate formed of an electrical insulator;
• heating elements formed on said substrate;
• conductive layers each formed on the part of the surface of each of said heating elements that is adjacent to and on either side of a heat generating portion of the heating element;
• and protective layers each formed on the surfaces of each of said conductive layers and said heat generating portion of each of said heat generating elements,
• the resistivity of said heating elements being not less than 1000 .mu..OMEGA..multidot.cm, and the thickness of said conductive layers at least in the vicinity of the heat generating portions of said thermal printing head being not more than 300 nm,
• the width of said heating elements being narrowed at said heat generating portions thereof.

A thermal printing head comprising:

• a substrate formed of an electrical insulator;
• heating elements formed on said substrate;
• conductive layers each formed on the part of the surface of each of said heating elements that is adjacent to and on either side of a heat generating portion of the heating element;
• and protective layers each formed on the surfaces of each of said conductive layers and said heat generating portion of each of said heat generating elements,
• the heating elements comprising a composite of an intermetallic compound and an electrically insulating material,
• the resistivity of said heating elements being not less than 10000 .mu..OMEGA..multidot.cm, and the thickness of said conductive layers at least in the vicinity of the heat generating portions of said thermal printing head being not more than 300 nm.
• the width of said heating elements being narrowed at said heat generating portions thereof.

A thermal printing head comprising:

• a substrate formed of an electrical insulator;
• heating elements formed on said substrate;
• conductive layers each formed on the part of the surface of each of said heating elements that is adjacent to and on either side of a heat generating portion of the heating element;
• and protective layers each formed on the surfaces of each of said conductive layers and said heat generating portion of each of said heat generating elements,
• the heating elements comprising a composite of an intermetallic metallic compound which is at least one selected from the group consisting of Nb.sub.5 Si.sub.3, NbSi.sub.2, Ta.sub.2 Si, Ta.sub.5 Si.sub.3, TaSi.sub.2, V.sub.3 Si, V.sub.5 Si.sub.3, VSi.sub.2, W.sub.5 Si.sub.3, WSi.sub.2, Cr.sub.3 Si, Cr.sub.5 Si.sub.3, CrSi, CrSi.sub.2, Mo.sub.3 Si, Mo.sub.3 Si.sub.2, MoSi.sub.2, Ti.sub.5 Si.sub.3, TiSi, TiSi.sub.2, Ni.sub.3 A1, NiA1, Ni.sub.2 A1.sub.3, CoA1, Co.sub.2 A1.sub.3, TiA1, ZrA1, ZrA1.sub.2, TaA1.sub.2 and TiA1.sub.3 and an electrically insulating material which is at least one selected from the group consisting of SiO.sub.2, A1.sub.2 O.sub.3, Ta.sub.2 O.sub.3, ZrO.sub.2, Y.sub.2 O.sub.3, Si.sub.3 N.sub.4, HfB, VB, MoB, LaB, TaB, TiB, CoB, NbB, WB, SiC, A1.sub.4.sub.4 C.sub.3, TaN, Si.sub.3 N.sub.4, A1N and BN, the resistivity of said heating elements being not less than 10000 .mu. .OMEGA.cm, and the thickness of said conductive layers at least in the vicinity of the heat generating portions of said thermal printing head being not more than 200 nm,
• the width of said heating elements being narrowed at said heat generating portions thereof.