| 摘要 |
PURPOSE:To control toner density accurately through a reflectivity detecting toner density sensor by narrowing down grain-size distribution by reducing a difference in grain size between the largest grains of carrier grains and the smallest grain to <=100mum. CONSTITUTION:Fluoropolymer-coated carrier grains whose surfaces are activated by being stirred mechanically in advance are classified by using two kinds of sieves having, e.g., 250 and 350mum sieve openings to select carriers having 25- 350mum grain size distribution, and those carriers and toner are mixed to produce a developer. Even after this developer is used to take 5,000 copies continuously by a copying machine equipped with a reflectivity detecting toner density sensor, toner density never varies and stable control is exercised; and the uneven distribution of the toner is not caused. |
