A set of solid ink sticks for a phase change ink jet printer has a common printer
key element that matches an insertion key in each in stick feed channel insertion
opening. The key element is formed in a portion of the perimeter of each ink stick
of the set. The key element is the same for all ink sticks of a set of ink sticks
intended for a particular model printer. Different sets of solid ink sticks intended
for different models of printers have different printer key elements in each set,
to prevent an ink stick intended for one model printer from being incorrectly inserted
into a different model printer.
