A toner cartridge according to one example embodiment includes a housing having a toner reservoir. An outlet port faces downward on a front of the housing near a first side of the housing. A linkage is positioned on the first side of the housing and has an engagement surface that is accessible at the rear of the housing. A projection is positioned on the first side of the housing and is movable between a first position and a second position. The projection is operatively connected to the linkage such that the projection moves upward from the first position to the second position when the engagement surface receives a forward force that is toward the front of the housing. The projection extends outward sideways from the first side when the projection is in the second position.