Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Creasing of paper can come, usually, from one of two causes:
1. the most common cause is, a defect in the paper pickup rollers, and/or the paper feed rollers. (In laser printers, the fuser rollers can crease paper also, though this is usually quite rare.)
2. the less common cause is, the paper is loaded incorrectly, or loosely, or aslant in the paper tray. Or, the paper can possibly be creased in a printer simply because it is unsuitable paper or has peculiar qualities of brittleness/moisture content/etc.
Your printer model is apparently a Brother color laser printer, with several years of use on it.
Check the paper, of course, and re-load it carefully, snugging up the paper guides.
After that, there are some other measures, including either paper pickup and paper feed roller cleaning, and/or 'halfway testing' to find out where the creasing is occurring, as the paper moves along the paper path through the printer.
Let me know what you would like to try, what you observe, and what advice you need, and I will guide you further toward a solution. Thanks.