Developing device, image forming apparatus, and image forming method

A method for forming an image in an image forming apparatus having an electrostatic latent image carrier, a developing device having a toner carrier on which first electrodes and second electrodes are formed and a toner supply unit supplying toner to the surface of a toner carrier to form a toner layer thereon, a pulsed power supply having a first pulse output unit outputting a first periodic pulse voltage and a second pulse output unit outputting a second periodic pulse voltage, a toner layer thickness regulator member and a smoothing circuit, the method comprising:

• carrying an electrostatic latent image;
• developing the electrostatic latent image by
• transferring the toner carried on the surface of the toner carrier by surface movement of the toner carrier to a developing region formed between the toner carrier and the electrostatic latent image carrier while causing the toner on the surface of the toner carrier to hop between the first electrodes aligned along a surface direction of the toner carrier and to which the first periodic pulse voltage is periodically applied and the second electrodes aligned along the surface direction of the toner carrier and to which the second periodic pulse voltage having a phase differing from a phase of the first periodic pulse voltage is periodically applied, and
• attaching the toner hopping therebetween to the electrostatic latent image carried on the surface of the electrostatic latent image carrier;
• outputting the first periodic pulse voltage having a mean potential with a polarity the same as a polarity of a normal toner charge;
• making the first periodic pulse voltage smooth to generate a smoothed first periodic pulse voltage as a direct voltage and applying the generated direct voltage the toner layer thickness regulator member;
• regulating, on the application of the generated direct voltage to the toner layer thickness regulator member, the thickness of the toner layer on the surface of the toner carrier in a region between a toner supply position at which the toner is supplied and the developing region formed between the toner carrier and the electrostatic latent image carrier before the toner layer on the surface of the toner carrier enters into the developing region.

An image forming apparatus comprising:

• an electrostatic latent image carrying means for carrying an electrostatic latent image;
• a developing means for developing the electrostatic latent image on the electrostatic latent image carrying means by
• transferring toner carried on a surface of a toner carrier by surface movement of the toner carrier to a developing region formed between the toner carrier and the electrostatic latent image carrying means while causing the toner on the surface of the toner carrier to hop between first electrodes aligned along a surface direction of the toner carrier and to which a first periodic pulse voltage is periodically applied and second electrodes aligned along the surface direction of the toner carrier and to which a second periodic pulse voltage having a phase differing from a phase of the first periodic pulse voltage is periodically applied, and
• attaching the toner hopping therebetween to the electrostatic latent image carried on the surface of the electrostatic latent image carrying means;
• a pulsed power supplying means for outputting the first periodic pulse voltage having a mean potential with a polarity the same as a polarity of a normal toner charge and outputting the second periodic pulse voltage;
• a smoothing means for making the first periodic pulse voltage smooth to generate a smoothed first periodic pulse voltage as a direct voltage;
• and
• a toner layer thickness regulating means for regulating, on receiving the applied direct voltage, the thickness of the toner layer on the surface of the toner carrier in a region between a toner supply position at which the toner is supplied and a developing region formed between the toner carrier and the electrostatic latent image carrying means before the toner layer on the surface of the toner carrier enters into the developing region.