In an image forming apparatus, a first detection part and a second detection part, each for detecting a position of a displacement member that changes its position according to a remaining amount of liquid in a sub-tank, are provided to a carriage carrying the sub-tank and a recording head, and a body of the image forming apparatus, respectively. Also, the clock control apparatus detects an operation clock frequency of a main CPU. Each segment has a wheel assembly including drive wheels. An electrical contact base is connected to the bottom wall of the adaptor casing and it has a conventional externally threaded outer electrical contact surface that would be received into a conventional incandescent lamp socket. The air with particles entrained in the air impacts the liquid surface with sufficient velocity to entrain the particles into the liquid but cause minor turbulence. The release switch selectively may be set to perform one of a plurality of functions, where the function of the release switch can be changed by the external device connected to the camera.