| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus using toner as a developer, wherein the concentration of the developer is judged with high accuracy by a simple method, so as to accurately perform the concentration control of the developer. <P>SOLUTION: A toner is blended with a fluorescent material in an amount of 1 to <10 wt.% smaller than the amount (10 to 40%) generally to be blended for developing fluorescence as a color material. A standard patch by the toner is formed on a transfer belt, and an ultraviolet illumination optical sensor 20 is arranged at the reading position thereof. The fluorescent material contained in the toner of the standard patch is excited by the ultraviolet illumination of the optical sensor 20 so as to illuminate fluorescence, the illumination wavelength of the fluorescence is received and is converted into a toner deposition amount by a sensor output/toner deposition amount data table, which is compared with a concentration data table beforehand stored in a memory device, a development bias is changed in accordance with the level of the toner concentration, and concentration control is performed. <P>COPYRIGHT: (C)2010,JPO&INPIT |
