Patent ID: 8509655

Claim:
An image forming apparatus, comprising: an image carrier configured by a positively charged single-layer electrophotographic photosensitive body; a charging device which is based on a contact charging method for charging a circumferential surface of the image carrier while making contact with the circumferential surface of the image carrier; a developing roller disposed to oppose the image carrier and carrying and conveying toner on the circumferential surface; a magnetic roller disposed to oppose the developing roller, the magnetic roller carrying and conveying a two-component developer including the toner on the circumferential surface; and a voltage application unit which applies a developing bias to the developing roller, wherein the frequency of an AC component of the developing bias applied by the voltage application unit is 2.6 to 4.2 kHz, and the charging device performs charging so as to satisfy Formula (I) below: 75 X +240 ≦Y≦ 600 (I) where, X indicates the frequency (kHz) of the AC component of the developing bias voltage and Y indicates the surface potential (V) of the image carrier.