| 摘要 |
PURPOSE:To dim a printer light source efficiently by positioning a dimming filter whose quantity of dimming is minimum at a specific position except in the direction of a light source optical path, and adjusting the quantity of light of the light source to the target quantity of light to the filter and inserting another filter into the light source optical path. CONSTITUTION:Dimming filters 3 (31-33) of cyan C, magenta M, and yellow Y have opening extents adjusted according to target values R, G, and B and voltage signals indicating the respective opening extents are outputted from potentiometers 81-83. The lowest voltage signal PS among those output voltages is detected and controlled with a reference voltage RV so that the filter contacts the outside of, for example, an optical path 35. Consequently, the filter having the lowest quantity of dimming among filters to be dimmed is positioned at the specific position outside the optical path 35, the quantity of light source light is made coincident with the target quantity of light, and other two filters are inserted into the optical path 35. Consequently, the quantity of light of the light source 1 is utilized most effectively.
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