| 摘要 |
PURPOSE:To realize highly accurate picture density control by adding a compound which does not practically show spectral absorption in the visible light zone, but has a definite spectral absorption peak in the near infrared zone to toner. CONSTITUTION:A compound which does not practically show spectral absorption in the visible wavelength zone of 400-700nm, but has a spectral absorption peak in the long wavelength zone of >=700nm is added to toner so that the toner itself can show spectral absorption in the wavelength zone of 700-1,000nm. Then a reference electrostatic pattern is developed by using the toner and the picture density is detected by using light having a wavelength of >=700nm, and then, signals to be used for controlling the picture density are caused to be generated. Therefore, the sensitivity of the output voltage of a photoreceptor element corresponding to the toner adhering quantity becomes extensively sharp and the detecting accuracy is improved. Accordingly, the control of the picture density does not fluctuate and stable density control is carried out even if the number of copying sheets increases. |
