An image forming apparatus includes a plurality of image forming units and a plurality of transfer units. The image forming units have corresponding image carriers and charging units. The image forming units form toner images of different colors on the corresponding image carriers. The transfer units face the corresponding image carriers to form transfer areas between the transfer units and the image carriers, and press a transfer member to the corresponding image carriers to transfer the toner images onto the transfer member at the transfer areas. The charging units include at least one corona-type charger and at least one contact-type charger. The image forming apparatus sets a first transfer condition for the transfer unit(s) corresponding to the image carrier(s) charged by the at least one corona-type charger and a second, separate transfer condition for the transfer unit(s) corresponding to the image carrier(s) charged by the at least one contact-type charger.