摘要 |
An LED printer head capable of reducing influence of a sub emission band by use of a rod lens array and thus prevent light of the sub emission band from reaching a development level. The LED printer head consists of an LED array of LEDs to emit light according to an image signal, which are arrayed at the resolution pitch P of not less than 600 dpi, and a multi-lens array for forming an emission image of the LED array on a photosensitive body. Each of the LEDs of the LED array has a main emission band of an emission spectrum and another sub emission band having a peak level of not less than 0.01 as a photosensitive intensity ratio R to the main emission spectrum, and a difference D between best total conjugate lengths at peak wavelengths of the main and sub emission bands by the multi-lens array is at least 0.15. Optical adjustment of the LED array and the multi-lens array is effected so that light of the main emission band is focused in a predetermined imaging relation on the predetermined photosensitive body.
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