Banks and payment networks are pressing state lawmakers to bar retailers from charging customers more to pay with credit cards than with debit cards or cash, Bloomberg News reported today. The laws’ supporters say that they are trying to protect consumers from unfair costs when they make purchases with credit cards. Utah has already passed a law banning such surcharges, and New Jersey may follow suit. In all, about 20 state legislatures are weighing legislation related to payment cards, according to the American Bankers Association. The move for state laws is an extension of a decade-long fight between retailers that include Home Depot Inc., Wal-Mart Stores Inc. and Target Corp., and members of the payments industry, including JPMorgan Chase & Co., the biggest U.S. credit-card lender, and Visa Inc. and Mastercard Inc., the largest networks, over “swipe” fees for debit and credit cards. Because retailers generally have to pay more to banks when their customers use credit cards than when they pay with debit cards, the banks are trying to prevent stores from steering buyers to debit transactions. At stake is an estimated $40 billion that banks take in each year from credit-card swipe fees, according to Madeline Aufseeser, a senior analyst with Boston-based consultancy Aite Group LLC.