PURPOSE: To form a distinct image pattern-like toner image, which generates no ground fog, by using the first developing sleeve and the second developing sleeve.
CONSTITUTION: The first developing sleeve 5 and the second developing sleeve 12 are used as each different developing device. In both of the developing sleeve, however, a magnet is placed suitably in the inside of the sleeve. To the first developing sleeve 5, DC bias is applied by an electric power supply 4, a picture is exposed and developed, and after that, ground fog is eliminated by the second developing sleeve 12 which has been grounded. In this case, the first developing sleeve 5 to which DC bias has been applied, and the second developing sleeve 12 which has been grounded are capable of selecting the relative moving direction of a photosensitive body 1 and the two developing devices 5, 12 by changing the application of the bias to each other by a switch 16, etc. By using such developing devices, it is possible to form a distinct image pattern-like toner image which generates no ground fog.
TAMURA YASUYUKI
TAKAHASHI TOORU
