| 摘要 |
PURPOSE:To obtain a toner image which is excellent durability and has high image density and no fogging of a white surface by using magnetic toner having specified particle size distribution and triboelectric charge quantity and asymmetric developing bias. CONSTITUTION:The magnetic toner T containing >=12 number % toner whose particle size is <=5mum, <=33 number % toner whose particle size is 8-12.7mum and <=2 volume % toner whose particle size is >=16mum and having the particle size distribution in which volume average particle size is 4-10mum is used. Bias impressing means S0 and S1 impress DC bias and asymmetric AC bias between a toner image carrier 22 and a latent image holding body 1 at a developing part A, so that alternating bias electric field is formed. The alternating bias electric field has a voltage component on a development side and a voltage component on an inverted development side. Then, the voltage component on the development side is made equal to or larger than the voltage component on the inverted development side, the impressing time of the voltage component on the development side is shorter than that of the voltage component of the inverted development side, and the magnetic toner T is moved from a toner carrier 22 to the latent image holding body 1 to develop an electrostatic charge image. Thus, the toner image which is excellent in durability and has high image density and no fogging of the white surface is obtained. |
