| 摘要 |
PROBLEM TO BE SOLVED: To further miniaturize a sensor by which an image can be monitored with high accuracy in a noncontact on-line manner and to monitor the image with high accuracy without being affected by a change in an image recording medium. SOLUTION: Density patches 39 of a sample image 38 on a sheet of paper 37 are formed as a yellow patch, a magenta patch and a cyan patch. LED's 41 as sensor light sources are installed so as to emit blue color light, green color light and red color light. Beams of light in the respective beams of light are shone at patches in colors as their complementary colors. Beam shaping means 49 which shape the beams of light from the LED's 41 are installed at the front of the respective LED's 41. Beams of reflected light from the respective density patches 39 are received, via respective lenses 43, by respective light receiving elements 44 which are installed on focal faces on the opposite side of the side of the sheet of paper 37 of the lenses 43. The electrostatic charge amount, the exposure amount or the like of a photoreceptor is corrected by the measured result of a fixed-image density sensor 40, and the image quality of an output image is controlled. |
