| 摘要 |
PURPOSE:To prevent dew condensation caused by the inflow of outdoor air and to prevent the deterioration of an image by coating an optical element positioned on an image forming optical path with transparent water absorbtive polymer in an optical device for a copying machine, etc. CONSTITUTION:The reflective surface of each mirror 14 to 16 (mirrors 17 to 19 and a lens 20, etc., can be included) for scanning the lower surface of a contact glass 13 is thinly coated with the transparent water absorbtive polymer 22. The outdoor air is taken in through an inlet 9 by use of a cooling fan 8 for cooling an original illuminating lamp 10 to make the air-flow around the lamp 10. Then, when the temperature of the 1st mirror 14 to the 3rd mirror 16 is lower than that of the outdoor air and the humidity of the air felt with the mirrors is high, the dew condensation occurs on the surface of the mirror, but the moisture content is absorbed by the transparent water absorbtive polymer 22, so that the surface of the mirror does not get fogged, thus, the deterioration of the image is prevented. |
