Developing apparatus and image forming apparatus using progressive wave electric field transport

A developing apparatus comprising a developer transportation member, which is (i) provided at a development area that faces an image supporting body that supports, on a surface thereof, an electrostatic latent image, and (ii) made by coating, with a surface protective layer, a plurality of electrodes so provided on a substrate that there are predetermined intervals between adjacent ones of the electrodes, the developing apparatus transporting, on the developer transportation member, developer by using a progressive wave electric field generated by applying multiphase voltages to the electrodes,

• a gap d, in meter, between the developer transportation member and the image supporting body, and a pitch λ, in meter, between adjacent ones of the electrodes satisfy d>λ and wherein:
• vp×R>f
• where vp, in millimeter per second, is a peripheral velocity of the image supporting body;
• R, in dot per millimeter, is a latent image writing resolution in a perimeter direction of the image supporting body;
• and f, in hertz, is a frequency of the voltages applied to the electrodes.

A developing apparatus comprising a developer transportation member, which is (i) provided at a development area that faces an image supporting body that supports, on a surface thereof, an electrostatic latent image, and (ii) made by coating, with a surface protective layer, a plurality of electrodes so provided on a substrate that there are predetermined intervals between adjacent ones of the electrodes, the developing apparatus transporting, on the developer transportation member, developer by using a progressive wave electric field generated by applying multiphase voltages to the electrodes,

• a gap d, in meter, between the developer transportation member and the image supporting body, and a pitch λ, in meter, between adjacent ones of the electrodes satisfy d>λ and wherein:
• |V0−V1|/d>104
• where V1, in volts, is an average value of the voltages applied to the electrodes;
• V0, in volts, is a charge potential of a non-image area of the image supporting body, and d, in meter, is the gap between the developer transportation member and the image supporting body.