PURPOSE: To suppress the heat releasing value of a light source of lighting to a low level without incresing the dimensions and weight of a reading head, by making a spectrum indicating the maximum light emitting quantity of the light source of lighting coincident with a spectrum indicating the maximum light receiving quantity of a photoreceptor element.
CONSTITUTION: In the arrangement of light sources 15a1∼15a5, intervals between the light sources 15a2∼15a4 are made regular ones L and intervals (l) between both end light sources 15a1 and 15a5 and their respective adjacent light sources 15a2 and 15a4 are made shorter than the interval L. Moreover, other light sources 15b1∼15b4 are arranged so as to face the midpoints of the light sources 15a1∼ 15a5 at regular intervals L. Since light sources, whose spectrum components almost coincide with the spectrum component of an image sensor (not shown in the figure) and, as a result, light quantity which is absorbed into the image sensor becomes more and the remaining light quantity which is discharged as heat energy becomes less, no heat releasing occurs. Moreover, since the arrangement of the light sources is made as mentioned above, an almost uniform light quantity is obtained at the end part of the light sources as well as the intermediate section.
UEISHI YOUICHI
FURUTO TAKASHI
