The Samsung ML-1630 is a compact laser printer. It prints using toner cartridges, and Samsung estimates they need to be replaced every three to six months depending on use. You'll know the cartridge needs to be replaced when the red light next to "Toner" on the front of the printer starts blinking, or when the ink starts printing thin or broken lines.
Turn off the printer and leave it off for five or more minutes -- this ensures that the internal components are cooled properly.
Push in the button just under the middle of the top cover and the lid will pop open; open the lid completely.
Find the toner cartridge located in the middle of the printer -- its about eight inches across. Grip the handle on the front and pull straight up to remove the cartridge. Dispose of it carefully.
Remove all packaging from the new toner cartridge, but do not use scissors or a knife to open the packaging.
Hold the cartridge upright and tip it slightly side-to-side to distribute the toner powder evenly. Set it down on a flat surface and remove the paper covering the cartridge. Set it in the printer where the old one was, and press down on both sides until it clicks into place. Close the lid and turn on the printer.