An image forming apparatus including an image forming device forming an image on a surface of a recording material; a recording material passage; a treatment liquid applicator including a tray containing a treatment liquid, a first roller applying the treatment liquid to the surface of the recording material, and a second roller drawing the treatment liquid from the tray to supply the treatment liquid to the first roller; a liquid level inclination detector detecting whether the surface of the treatment liquid is inclined; a treatment liquid supplying device supplying the treatment liquid to the tray; and a controller connected with liquid level detector and the treatment liquid supplying device. The controller stops the operation of the treatment liquid supplying device when determining according to the detection result of the liquid level detector that the surface of the treatment liquid is inclined in a predetermined amount or more.