In an inverter the input signal is reversed ( so input posative , outputs negative) with an open collector you have to provide a Load resistor to pull the collector to posative supply.
No Open Collector in not a gate. It is a typo of a output that gates can have.
In general we have a two types of a outputs.
The complementary (totem pole) outputs. And open collector output. http://en.wikipedia.org/wiki/Open_collector