| 摘要 |
PROBLEM TO BE SOLVED: To realize stable fixation even in the case of using toner different in softening point and to reduce the power consumption of a fixing device by providing an image forming part with a detection means detecting the density information of an image and changing fixing temperature in accordance with the image density detected by the detection means. SOLUTION: The image of an original 51 is projected to an image pickup element 53. An analog image signal outputted from the element 53 is transmitted to an image signal processing circuit 54, converted into a pixel image signal having an output level corresponding to the density of the image and transmitted to a pulse width modulation circuit 55. The output signal of a pulse width modulation circuit 55 is supplied to either input of an AND gate 60, and clock pulses whose number corresponds to the density of each pixel are outputted. The video counted number of each pixel is supplied to a CPU 63. The CPU 63 calculates the rate of the density of each color per original from the video counted number of each pixel and each color, decides optimum fixing temperature in the case of color mixture and outputs a color mixture fixing temperature to the controller 40 of the fixing device 10. |
