The invention provides an image forming apparatus, comprising: an electrophotographic photoreceptor, a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and a cleaning unit; the electrophotographic photoreceptor having an outermost layer containing a charge transporting material and at least one curable resin selected from the group consisting of a phenol resin, an epoxy resin and a melamine resin, and the toner having an ammonium ion concentration as determined by ion chromatography of from about 50 ppm to about 300 ppm.