Development agent concentration detection manner, and development agent concentration control manner

摘要

PURPOSE: To precisely detect the concentration of a developer. ;CONSTITUTION: The concn. of the developer is detected in the vicinity of 1.5V where excellent sensitivity of the output voltage of a photosensor S2 is secured an image density output level for attaining the detection is 58. For instance, when the gap (S-D gap) between a photoreceptor drum 1 and a developing roller is increased, the output voltage of the photosensor is increased to 1.8V (the point of Q) at the image density output level of 58. For making the output voltage 1.5V, the image density output level (for instance, the intensity of laser light) is increased by about 10 levels to obtain the level of 68.;COPYRIGHT: (C)1996,JPO