Patent ID: 7925174

Claim:
An image forming apparatus, comprising: a latent image carrier to carry a latent image on a surface thereof; a developing unit to develop the latent image with developer including toner and carrier into a toner image; a developer bearing member to carry the developer; a first detector to detect an amount of toner adhesion per unit area of the toner image developed by the developing unit; a second detector to detect humidity; and a controller to calculate an index that indicates toner chargeability of the carrier of the developer contained in the developing unit based on detection results of the amount of toner adhesion obtained by the first detector and perform a given control process based on calculation results thereof, the controller including a data storage unit to store an algorithm to correct the index to a specific value according to a specific humidity, based on detection results of the humidity obtained by the second detector, the controller correcting the index obtained based on the amount of toner adhesion based on the algorithm.