This patent is directed to an injector and a method of assembling the injector, and, in particular, to a prefilled injector and a method of assembling the prefilled injector. 
Injectors are used to deliver medical fluids, such as liquid drugs, to a patient.  In particular, the injector will provide the fluid to the patient through a needle, cannula or catheter that defines a flow path into the patient.  Certain injectors have a reservoir that is assembled by the manufacturer already connected to the flow path.  However, these reservoirs are typically provided empty by the manufacturer to the patient or healthcare provider (e.g., doctor, nurse, healthcare assistant, etc.),  and then the reservoir is filled at the time of use.  Alternatively, the injector may be used in combination with a reservoir that is provided to the patient or healthcare provider prefilled. 
In either case, the injector must be prepared prior to use.  For example, if the reservoir is provided empty, then the reservoir must be filled.  To do this, a syringe is filled with the drug to be delivered, and then the drug is injected into the reservoir through an inlet port.  Prior to the injection, the inlet port must be sterilized by swabbing the outer surface with an alcohol wipe, for example.  Similarly, before the prefilled reservoir is connected to the flow path in the alternative injector, the mating connectors must be sterilized, by swabbing the surface with an alcohol wipe. 
In either event, the use of the injector requires additional material and time. 
As set forth in more detail below, the present disclosure sets forth an improved injector embodying advantageous alternatives to the conventional devices and methods discussed above.