| 摘要 |
PURPOSE:To obtain a sharp two color image with simple constitution by using a magnetic developer consisting of a mixture composed of a toner which is electrostatically charged to a specified polarity by contact with a magnetic carrier, a material which is electrostatically charged to a reverse polarity by contact with said toner, and a toner which is not electrostatically charged by friction. CONSTITUTION:A photosensitive drum 1 is electrostatically charged uniformly to +800V by the 1st corona charger (CC) and thereafter the drum is exposed with a two-color original of red and black, is then electrostatically charged to a reverse polarity by the 2nd CC 6 and is again exposed through a cut filter 8. A secondary electrostatic latent image is formed thereon. A bias voltage of -80V is impressed thereon from a DC power source 20 and the latent image is developed. A mixture composed of a magnetic carrier, a red toner which is electrostatically charged to a specified polarity by contact with the magnetic carrier, a material which is charged frictionally to a reverse characteristic by contact with the toner, and a black toner which is not frictionally charged is used for the developer. A sharp image is thus obtd. |
