Image forming apparatus and image forming method with controllable suction

An image forming method for an image forming apparatus including

• a housing provided with an opening opposed to a developer carrying member that carries and transports developer;
• a collecting member provided along an edge of the opening at a downstream end of the opening in a transporting direction in which the developer carrying member transports the developer, the collecting member being capable of coming into contact with and separating from the developer carrying member;
• a sealing member provided along an edge of the opening at an upstream end of the opening in the transporting direction;
• a suction member that at least sucks the developer removed from the developer carrying member into the housing;
• a suction path provided between the opening and the suction member;
• and
• an opening-closing unit provided in the suction path, the opening-closing unit opening or closing the suction path,
• the method comprising:
• controlling the opening-closing unit so as to open the suction path from a closed state at a time that is before separation of the collecting member from the developer carrying member and a predetermined time period after the time of contact between the collecting member and the developer carrying member.