Michael Scott landed them as a supplier at the Northeastern Mid-Market Office Supply Convention in Philadelphia, Pennsylvania. Michael discussed opening an account with Hammermill to sell their paper with Evan during "The Convention." This was an incredible feat as previously Hammermill was an exclusive supplier for Staples.
Later, in "Business Ethics," it is revealed that the Dunder Mifflin representative for Hammermill is Bruce Meyers (Mentioned Characters). Meredith Palmer revealed during an ethics seminar that, for cheaper prices and Outback steak coupons, she had slept with Bruce about once a month for the past six years (continuity error). This exchange continued after the fact for an unknown amount of time.