| 摘要 |
PURPOSE:To develop a sharp image by freely adjusting the size of a spacing between a developer carrier and an image support by an adjusting means and regulating the frequency of the voltage to be impressed between the carrier and the support according to the size of the spacing at the time of impressing the AC voltage between the carrier and the support, thereby applying the volt age subjected to such frequency regulation between the carrier and the support. CONSTITUTION:The toner T in a hopper 12 of a developing device 10 is supplied to a developing roller 16 while the toner is agitated by the rotation of a supply roller 22. The toner T is conveyed to a developing region D by the toner conveying force on the surface of the roller 16. A photosensitive drum 14 which faces this roller 16 and on which an electrostatic latent image is formed is disposed apart the spacing (d) is rotated in an arrow D direction. The prescribed voltage superposed with DC and AC voltages is impressed between the roller 16 and the drum 14 from an AC bias power supply 26. A frequency dividing circuit which has an oscillator, comparator, sine modulator, etc., and changes frequencies automatically and an adjuster which adjusts the spacing (d) are provided on the power supply 26. The frequency of the AC voltage is thus varied by adjusting the spacing (d).
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