IMAGE FORMING APPARATUS

To improve transfer efficiency by effectively supplying fine particles to a surface of a photoconductor drum.SOLUTION: An image forming apparatus has a rotatable developer carrier that carries developer composed of toner particles and transfer promoting particles adhered to the surface of each of the toner particles. When a pressing force pressing the developer carrier to an image carrier is F, and the total number of the transfer promoting particles interposed between the toner particle and the image carrier is N, the relationship between an adhesive force Ft formed between the transfer promoting particles and the toner particle measured when the transfer promoting particles are pressed against the toner particle at a pressing force F/N per unit transfer promoting particle, and an adhesive force Fdr formed between the transfer promoting particles and the image carrier measured when the transfer promoting particles are pressed against the image carrier at the pressing force F/N, satisfies Ft