| 摘要 |
PROBLEM TO BE SOLVED: To measure the concentration of both color toner YMC and black toner K by combining a single light emitting element with a light receiving element. SOLUTION: A toner mark transfer part 101 transfers a halftone pattern such as a horizontal line pattern or an oblique line pattern on a belt by plural electrostatic recording units 24. A toner concentration measuring part 102 calculates the concentration control parameter of light emitting time and light emitting current corresponding to toner adhesive amount based on the rate of reflected light (space width between lines) at a part where the toner does not exist in the read signal of the halftone pattern by a sensor unit 26 and light (line width) attenuated by scattering at a part where the toner exists. |
