Samsung CLP 500N - Manual (Page 125)

M AINTAINING Y OUR P RINTER 6.7
6
4 Slide the toner cartridge back into the printer.
5 Close the left cover. Make sure that the cover is securely
latched.
If you are installed the toner cartridges wrong, the left
cover will not close properly. Check again to make sure the
colors correspond. Never use force to close the cover.