| 摘要 |
PURPOSE:To reproduce a picture with excellent gradation by providing a density detection means detecting a density of a visual image formed on an image medium with a visual image forming means based on one predetermined reference data or over and a correction means correcting a density conversion coefficient in response to the density detected by the density detection means to the device. CONSTITUTION:A photodetector 23 consists of a laser diode 231 as a light emitting element, a photodiode 232 as a light receiving element and an amplifier 233 and detects a reflecting luminous quantity from a a visual image (hereinafter called a patch) formed on a photosensitive drum 14. The wavelength of a laser beam radiating from a laser diode 231 is 960nm. Since the sensitivity of the photosensitive drum 14 is between 780-800nm, the effect of the laser beam is less. An A/D converter 24 converts an analog signal from the luminous quantity detector 23 into a digital signal. A CPU 3 as a correction means corrects a density conversion coefficient of a density converter 2 in response to the density detected by the photodetector 23. |
