MICR toner cartridges are sold for laser printers so you can print checks that are magnetically encoded to satisfy banks and the scanners at retail stores. I discovered an added advantage by accident. The MICR toner in the cartridges sold at checksnet.com is darker than regular toner and other MICR toner I found. This has allowed me to use printer darkness settings as low as 1 (on the 1 to 10 scale) and I still get solid black text when I print regular documents. Bottom line is, after some testing, I figured out that using the MICR toner cartridge is cheaper (more printed pages) than buying several regular toner cartridges for my laser printer.