Developing device and image forming apparatus including inclined transport screw

An image forming apparatus, comprising a developing device that develops a latent image formed on an image support member using developer containing toner, wherein said developing device includes:

• at least three transport screws that are provided in a casing and rotate about a respective rotational axis for agitating and transporting said developer, the at least three transport screws including:
• a supply transport screw and a receiving transport screw arranged in a top and bottom relationship, the rotational axes of the supply transport screw and the receiving transport screw being mutually parallel in relation to said image support member;
• and
• an inclined transport screw arranged at an incline between one end of said supply transport screw and an other end of said receiving transport screw;
• a supply for supplying new carrier into said casing;
• and
• a discharge port and discharge device for discharging part of the developer housed in said casing to an outside of the device, said discharge port being provided on said casing adjacent to an upper part of said inclined transport screw and upstream of said supply transport screw.