Image forming apparatus

The image forming apparatus includes a chassis having first and second side surfaces of the chassis; an ink sheet cartridge detachably disposed between the first and second side surfaces of the chassis; a take-up reel engaging the take-up bobbin; and a feed reel engaging the feed bobbin. The ink sheet cartridge includes a casing, a take-up bobbin and a feed bobbin disposed within the casing, first and second compression coil springs respectively coupled to circumferences of portions of the take-up bobbin and the feed bobbin so as to bias the take-up bobbin and the feed bobbin in the longitudinal direction. At least one of the take-up reel and the feed reel engages the corresponding one of the take-up bobbin and the feed bobbin without a biasing member being disposed between the first surface of the chassis and the corresponding one of the take-up bobbin and the feed bobbin.