| 摘要 |
An optical LED printhead for hard copy printing using a photoconductive transfer system. The printhead includes a linear array of LED's formed by the side-by-side mounting of modular circuit tiles, each containing LED and driver chips. The tiles are bonded to a backing plate constructed of a material with the same thermal coefficient of expansion as the tiles. Slots at the ends and in the middle of the backing plate are aligned with pins in a heat sink of dissimilar material. Differential thermal expansion between the heat sink and the backing plate is controlled by the slot and pin arrangement to allow relative movement in predefined directions which relieve stress but which do not degrade the alignment of the LED's. A printed circuit board and the backing plate are fastened to the heat sink through spring loaded screws extending through oversized holes. Upon mounting, the circuit tiles are located in a rectangular opening in the printed circuit board.
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