An image forming apparatus includes: an image forming unit having a plurality of photoconductor drums arranged in tandem; a conveyor belt arranged opposite to the plurality of photoconductor drums and configured to convey a recording sheet; a cleaning unit having a cleaning member positioned in contact with the conveyor belt to collect substance adhering to the conveyor belt, and a receptacle configured to store the substance collected by the cleaning member, wherein the cleaning unit is arranged on the same side as the image forming unit with respect to the conveyor belt; and a positioning member configured to cause the cleaning member to be positioned at a contacting position where the cleaning member contacts with the conveyor belt and at a spaced-apart position where the cleaning member is away from the conveyor belt.