The Samsung ER-5100 uses 44mm bond paper rolls.and an ERC-18 ink ribbon cartridge. As with all cash registers that use bond or impact paper always keep paper in both sides and never re-ink the cartridge. When the print becomes faded only use a factory inked and sealed ribbon. Operating without paper installed or a re-inked ribbon could cause serious damage to this register and they are no longer made and parts are becoming scarce.