Method of producing protected thermal head

A method of producing a protected thermal head for use in sliding contact printing applications, comprising the steps of:

• preparing a thermal head comprising a substrate, a heat generating layer on the substrate and a pair of electrodes on said heat generating layer;
• and
• depositing, by sputtering, a wear-resistant protective film comprising Si, O and N on said thermal head in a sputtering gas, wherein said wear-resistant protective film is formed by sputtering at least one first layer under no bias or a first bias and at least one second layer under a larger bias than said no or first bias used to form said first layer, wherein said first layer comprises a concentration of said sputtering gas of 0-3 at % and wherein a voltage of said larger bias is in a range between −50 V and −200 V and a voltage of said no or said first bias is in a range of from 0 to ⅔ of said voltage of said larger bias.

A method of producing a protected thermal head for use in sliding contact printing applications, comprising the steps of:

• preparing a thermal head comprising a substrate, a heat generating layer on the substrate and a pair of electrodes on said heat generating layer, and
• depositing, by sputtering, a wear-resistant protective film comprising Si, O and N on said thermal head in a sputtering gas to form a protected thermal head for use in sliding contact printing applications, wherein said wear-resistant protective film is formed by sputtering at least one first layer under no bias or a first bias and at least one second layer under a larger bias than said no or first bias used to form said first layer, wherein said wear-resistant protective film has a thickness of at least 1.0 μm and wherein a voltage of said larger bias is in a range between −50 V and −200 V and a voltage of said no or said first bias is in a range of from 0 to ⅔ of said voltage of said larger bias.