| 摘要 |
The drive circuit elements mounted on a heat resistant substrate for composing a thermal head were covered with a protective layer made of epoxy resin in the prior art. This epoxy resin is greatly different from the heat resistant substrate in the coefficient of linear expansion and is relatively high in Young's modulus, and therefore due to rise or fall of temperature in the manufacturing process, the shrinkage of the protective layer is greater than the shrinkage of the heat resistant substrate, and hence the heat resistant substrate is warped. Such warp may be eliminated by selecting a resin having a coefficient of linear expansion almost same as the coefficient of linear expansion of the heat resistant substrate as the material for the protective layer.
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