Image forming apparatus and toner set

An image forming apparatus comprising:

• a first electrostatic latent image bearer configured to bear a colored toner image;
• a first electrostatic latent image forming device configured to form a first electrostatic latent image on the first electrostatic latent image bearer;
• a first developing device containing a colored toner, configured to develop the first electrostatic latent image formed on the first electrostatic latent image bearer with the colored toner to form the colored toner image;
• a second electrostatic latent image bearer configured to bear a special-color toner image;
• a second electrostatic latent image forming device configured to form a second electrostatic latent image on the second electrostatic latent image bearer;
• a second developing device containing a special-color toner, configured to develop the second electrostatic latent image formed on the second electrostatic latent image bearer with the special-color toner to form the special-color toner image;
• a primary transfer device configured to transfer the colored toner image and the special-color toner image onto a surface of an intermediate image bearer in an overlapping manner to form a composite toner image;
• a secondary transfer device configured to transfer the composite toner image from the intermediate image bearer onto a surface of a recording medium;
• and
• a fixing device configured to fix the composite toner image on the surface of the recording medium,
• wherein the colored toner comprises a carbon black,
• wherein the special-color toner comprises a metallic pigment, and
• wherein an absolute difference in volume resistivity between the special-color toner and the colored toner is 0.30 log Ω cm or less.