| 摘要 |
PURPOSE:To prevent generation of a clearance between a substrate and a heat radiation plate and enhance a resolution by providing a thermal compound layer between the substrate and the heat radiation plate located under the former and constituting the heat radiation plate with plural pieces of metallic sheet whose coefficient of thermal expansion becomes low as the heat irradiation plate becomes remote from the substrate. CONSTITUTION:A heat irradiation plate 5 such as of aluminum, etc. is provided under a substrate 1 through the intermediary of a thermal compound layer 6 and the heat radiation plate 5 is constituted with plural pieces of metallic sheet 7, 8 whose coefficient of thermal expansion varies. If the coefficient of thermal expansion of the metallic sheet 7 is higher than that of the metallic sheet 8, no clearance is generated between the substrate 1 and the heat radiation plate 5 because of the warping of the heat radiation plate 5 and the compound layer 6 in the same direction, even if the substrate 1 is warped due to the heat generation by an exothermic resistance 2. Thus it is possible to obtain a recorded image with less unevenness of recording density and high resolution. |
