Image forming apparatus and process cartridge

An image forming apparatus, comprising:

• an electrophotographic photoreceptor;
• a charging unit that charges a surface of the electrophotographic photoreceptor;
• an exposure unit that exposes the charged surface of the electrophotographic photoreceptor to form an electrostatic latent image;
• a developing unit that develops the electrostatic latent image using a toner to form a toner image;
• a transfer unit that transfers the toner image from the surface of the electrophotographic photoreceptor to a transfer material or an intermediate transfer medium;
• a fixing unit that fixes the transferred toner image on a recording material;
• and
• a cleaning unit that removes toner remaining on the surface of the electrophotographic photoreceptor after completion of the transfer of the toner image;
• 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,
• the toner including a polyester resin, the polyester resin having been functionalized to include an ammonium ion, and
• the toner having an ammonium ion concentration as determined by ion chromatography of from about 50 ppm to about 300 ppm.