| 摘要 |
PURPOSE:To extend the life of a light emitting diode by differentiating the gap positions between the printed circuit boards provided in the vicinity of one and other long sides of a base stand in the longitudinal direction of the base stand and setting the gaps in an obliquely crossing or stepped state in the longitudinal direction. CONSTITUTION:The position of the gaps 26 between light emitting diodes 16 provided at the position corresponding to the gap 12 of printed circuit boards 5a, 5b and the position of the gap 27 between the light emitting diodes 16 provided at the position corresponding to the gap 9 between printed circuit boards 4a, 4b are made different. When the temp. of this optical printing head rises, the optical printing head is bent in an upwardly protruding state at the part of the gap 26 by the difference in the coefficient of thermal expansion between a base stand 1 and the circuit board 5a but, since the gap 12 is shifted from the gap 9 of the circuit board 4a in the gap 26, there is no effect of heat strain due to the circuit board 4a. Therefore, the heat strain of the light emitting diodes 16 adjacent to the gap 26 is reduced by half as compared with conventional one and the mutual damage of the light emitting diodes 16 due to heat strain is not generated. |
