A comb opener is a manually-operated device that is used to pull the prongs of the plastic binding comb open so that a punched document can be inserted. The comb opener has small teeth that gently pull on each of the prongs and pull them open, exposing the tip of each prong (onto which the document is placed). The vast majority of comb binding machines have built-in comb openers, but they are also sold as stand-alone units for high-volume production environments.
Manual comb openers have two sets of teeth – long teeth and small, angled teeth. The long teeth are what holds the comb in place, and the small, angled teeth are what pull the comb open. Start by placing the comb so that the individual loops fit into the spaces between the long teeth. The solid back of the comb should rest against the back side against the long teeth. Once the comb is in place, pull the handle to engage the small teeth and gently pry the prongs open. Insert your document into the comb by aligning the 19 holes with the 19 prongs, then push the handle back to its original position to close the comb and finish the bind.