I'm running a Royal Sovereign cold laminator in my shop (54") and had similar issues. I couldn't physically see an issue with the machine, but due to pressure being uneven across the rollers, it would cause the lam and substrate to pull unevenly, resulting in wrinkles and air bubbles. I asked a RS tech about it at a trade show and he told me I needed a pressure gauge and gave me their parts department number. I don't have that number here, but essentially, it's a flat piece of thin aluminum with a eyelet on one end that hooks onto what is essentially a fish scale. You hook it scale onto the edge of the feed table and let the rollers pull the aluminum through until it pulls pressure. While it's still running, you can measure the roller pressure. If you have the sides off the laminator, there is a large allen head screw that adjusts the pressure on each side. Just measure the middle pressure and then adjust the side pressures to be the same and your materials will go through evenly.
Sorry I don't know the exact name of the tool they gave me. If I remember correctly, it was under $70 to get it from them. Well worth it in my opinion. They are one of the few companies that don't charge a billion dollars for a simple part in this business and their service dept is fantastic.
