Thermal head
AssigneeFuji Photo Film Co., Ltd.
InventorTaihei Noshita
Life of this patent
Estimating the term…
Abstract
A thermal head has a protective coating of heating elements. The protective coating includes an insulating protective layer and an electrically conductive protective layer formed above the insulating protective layer. The electrically conductive protective layer covers at least a region of the insulating protective layer under which an under-glaze heat-accumulating layer is located and does not overlie at least one of the negative and positive electrode layers in other regions than the region. The thermal head can prevent abnormal current flow due to pinholes of the insulating protective layer formed under the electrically conductive protective layer, exhibit high reliability over an extended period of time and perform thermal recording of high-quality images consistently over an extended period of operation.
Claims5
A thermal head comprising:
- at least one heating element,
- at least one negative electrode layer and at least one positive electrode layer formed on said heating element,
- a protective coating formed on said heating element, and
- an under-glaze heat-accumulating layer formed under said heating element,
- wherein said protective coating includes:
- an insulating protective layer formed on said negative electrode layer and said positive electrode layer, and
- an electrically conductive protective layer formed above said insulating protective layer,
- wherein said electrically conductive protective layer covers a first region of said insulating protective layer under which said under-glaze heat-accumulating layer is located and does not overlie other regions of said insulating protective layer than said first region.
A thermal head comprising:
- at least one heating element,
- at least one negative electrode layer and at least one positive electrode layer formed on said heating element,
- a protective coating formed on said heating element, and
- an under-glaze heat-accumulating layer formed under said heating element,
- wherein said protective coating includes:
- an insulating protective layer formed on said negative electrode layer and said positive electrode layer, and
- an electrically conductive protective layer formed above said insulating protective layer,
- wherein said electrically conductive protective layer covers a region of said insulating protective layer under which said under-glaze heat-accumulating layer and said negative electrode layer are located and does not overlie an area of said insulating protective layer where said positive electrode layer alone is disposed.
Dependencies are inferred from the claim text.