Patent ID: 7607844

Claim:
An image forming apparatus, comprising: a chassis having first and second side surfaces; an ink sheet cartridge detachably disposed between the first and second side surfaces of the chassis, the ink sheet cartridge including a casing, a take-up bobbin disposed within the casing, a feed bobbin disposed within the casing, a film wound around the take-up bobbin and the feed bobbin, a first compression coil spring coupled to a circumference of a portion of the take-up bobbin so as to bias the take-up bobbin in a longitudinal direction of the ink sheet cartridge, and a second compression coil spring coupled to a circumference of a portion of the feed bobbin so as to bias the feed bobbin in the longitudinal direction; a take-up reel rotatably supported by the first side surface of the chassis and including an engagement portion that engages the take-up bobbin when the ink sheet cartridge is installed in the chassis; and a feed reel rotatably supported by the first side surface of the chassis and including an engagement portion that engages the feed bobbin when the ink sheet cartridge is installed in the chassis, at least one of the take-up reel and the feed reel selectively engaging 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, the casing of the ink sheet cartridge being moved in the longitudinal direction with respect to at least one of the engagement portions of the take-up reel and the feed reel by a predetermined amount that is equal to an ejection stroke between an installed position of the ink sheet cartridge and an ejected position of the ink sheet cartridge when the ink sheet cartridge is moved in the longitudinal direction between the installed position and the ejected position, at least one of the first and second compression coil springs of the ink sheet cartridge being compressed by the predetermined amount when the ink sheet cartridge is located at the installed position.