Patent ID: 7907856

Claim:
An apparatus for developing a latent image with developing material on a latent image carrier, comprising: a toner carrier coated with a surface layer; multiple electrodes arranged at intervals on a surface of the toner carrier; a metering blade for controlling a thinness of the developing material including a toner layer on the toner carrier; a potential difference is formed between even-numbered electrodes and odd-numbered electrodes of said electrodes by applying a first pulse voltage to the even-numbered electrodes and a second pulse voltage to the odd-numbered electrodes so that toner on the surface of the toner carrier moves back and forth between said electrodes, where the first pulse voltage and the second pulse voltage are in different phases, the toner moving back and forth between said electrodes is conveyed to a position facing the latent image carrier by movement of the surface of the toner carrier and thereby is caused to adhere to the latent image on the latent image carrier, and when a pitch between said electrodes is p μm and a distance between the toner carrier and the latent image carrier is d μm, p μm<d μm in order to reduce a transfer of toner from the latent image carrier to the toner carrier; wherein the developing material contains toner but no carrier particles, and wherein the surface layer of the toner carrier includes a material to charge the toner to a normal charge polarity of the toner by friction with the toner.