A printer includes a main body, a development cartridge attachable to and detachable from the main body, the development cartridge to supply toner contained in a toner container to an electrostatic latent image formed on a photoconductor, to form a visible toner image, a mounting portion including a toner inlet portion connected to the toner container, where a toner cartridge usable to refill toner in the toner container is mountable to the mounting portion, an inlet shutter rotatably provided in the mounting portion to be rotatable together with the toner cartridge, the inlet shutter rotatable between a blocking position to block the toner inlet portion from receiving toner and an inlet position to open the toner inlet portion to receive toner, a locking unit to selectively lock and unlock the inlet shutter, and a controller to control the locking unit to selectively lock and unlock the inlet shutter based on whether the toner cartridge is mounted to the mounting portion.