A professional who tends machine that automatically seals envelopes and prints postage and postmark onto envelopes or tape to be affixed onto packages. Responsibilities include:

• Turns indicator dials to specified letters and numbers to be printed.
• Starts machine and positions envelopes onto feed tray or secures roll of tape on machine spindles.
• Removes postmarked envelopes or tape.
• May weigh articles to determine required postage, using scale and postal code book.
• May be designated according to particular function as Canceling-Machine Operator; Envelope-Sealing-Machine Operator; Stamping-Machine Operator.