| 摘要 |
PROBLEM TO BE SOLVED: To provide an image density detecting mechanism capable of accurately detecting an image density by minimizing variation of a density measurement output. SOLUTION: A diffusion cylinder (a diffusion plate) 2c provided between a photodiode 5a for monitoring a quantity of an emitted detection light emitted from an LED 4 and the LED 4 is integrally formed with an LED holder (a positioning member) 2. The photodiodes 5a, 5b are fixed to a sensor holder (a fixing member) 1 and the LED holder 2 is positioned to be fixed to the sensor holder 1. Since the position accuracy of optical parts such as the LED 4, the photodiodes 5a, 5b and the like is controlled by the two components of the LED holder 2 and the sensor holder 1, it is possible to accurately detect the image density by minimizing variation of the density measurement output due to the environmental change. |
