Image forming apparatus capable of switching image adjustment process according to an environment condition

An image forming apparatus, comprising:

• a rotatable photosensitive member;
• image forming means including charging means for charging said photosensitive member, exposing means for exposing said photosensitive member to form an electrostatic image thereon, developing means for developing the electrostatic image formed on said photosensitive member by said exposing means, with toner, and transferring means for transferring a toner image developed by said developing means onto a recording material;
• fixing means for fixing the toner image transferred by said transferring means onto the recording material;
• a humidity sensor for detecting an environment humidity of the image forming apparatus;
• a heater for heating said photosensitive member;
• and
• control means for, when said fixing means having a temperature lower than a predetermined temperature is heated up to an image formation allowable temperature, controlling said image forming means to (i) execute a first adjustment process for adjusting an image forming condition of said image forming means in a period of heating said fixing means up to the image formation allowable temperature in a case said humidity sensor detects a first humidity level, and (ii) execute a second adjustment process for which a required time period is longer than that for the first adjustment process in a period of heating said fixing means up to the image formation allowable temperature in a case in which said humidity sensor detects a second humidity level higher than the first humidity level.