The present invention provides a drink supply canister holder for a beverage dispensing apparatus for a residential refrigerator. Tubes may be accessed from a single direction, thereby eliminating the need for significant excavation around a buried tube. In one embodiment, the body of the socket contact comprises a head, a spring coupled to the head, and a shaft coupled to the spring; no outer shell is needed for the spring, as the non-conductive sides of the socket hole serve that function. A pair of left and right pinions are arranged at left and right ends of the rotary shaft, respectively, such that the pair of left and right pinions and the rotary shaft form a one-piece assembly. The inverter chamber detachably accommodates the inverter assembly. The shutter includes a latch to hold the shutter in place when the shutter covers the waste toner discharge port.