PURPOSE: To perform the development with a high picture density and less photographic fog, by holding the development potential of a background part in a potential lower than the development start potential before the development and allowing electric charges of opposite signs to appear in toner particles which are peeled from each other in an electric field.
CONSTITUTION: A magnetic toner 9 whose quantity is regulated by a tuft regulating plate 10 used as a destaticizing member also is formed into a magnetic brush where the development potential of the background part is lower than the development start potential by controlling a toner layer potential on a developing roll 11. When toner particles put under the action of the electric field generated by a photoreceptor 4 and a sleeve 12, an electric charge is generated in them. The movement speed of the magnetic brush is about 5 times as high as that of the photoreceptor; and when the magnetic brush brought into contact with the photoreceptor is peeled between toner particles, electric charge exchange occurs between particles, and electric charges of opposite signs required for the development appear in toners on the side of the photoreceptor 4 and the side of the sleeve 12, and the development is performed. Consequently, the stable development is possible which is superior in resolving power and is not affected by a secular change and an environmental change.
NOZUNA TSUNEO
MASUDA KOUJI
SAITOU KOUICHI
MARUYAMA KAZUO
FUJIMURA YOSHIHIKO
SUEMITSU YUUJI
YAMAMOTO TOSHIROU
| JPS5678846A | 1981-06-29 |
Next Patent: DEVICE FOR DEVELOPING ELECTROSTATIC LATENT IMAGE WITH MAGNETIC TONER