What is a Fuser Unit?

Have you ever noticed that paper is warm right when it comes out of your laser printer? Why does this happen?

A fuser unit is what makes paper warm when it is fresh out of the printer. Within the printer, a fuser unit is a pair of heated rollers that presses the toner into the paper being printed on.

To create the desired text and images, toner particles are pulled to the paper as it passes through the imaging drum. Next, the paper moves through the fusers to permanently melt the toner into the fibers of the paper. Heat and pressure applied to the fuser unit allow this function to take place. Once the paper passes through the fuser assembly, it is rolled out to the output tray for you to pick up.

Why doesn’t the paper catch fire from the heat?

Because the paper passes through the fuser rollers so quickly, there is no time for the paper to ignite.

Why does the fuser assembly need to be replaced?

A fuser unit needs replacing due to the constant wear within the printer. Dust particles from the paper and the toner latch on to parts of the printer and cause damage.

As toner is a powder, it commonly sprays onto parts within the printer when it is being attracted to the paper. The fast movement of the papers through the printer causes an accumulation of dust.

The build-up of these particles scratches the fuser unit, which creates lines on the printed output. While most printers have alerts that notify you when your fuser unit needs to be replaced, lines on your printed pages will signify that you need a new fuser! Fuser replacements can be purchased separately, but for some printer models they are included in the printer maintenance kit.