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What is an Image Drum?

The drum of a laser printer is responsible for transferring the toner and image or text to the paper. It has several different names, and you might hear it referred to as the image drum, imaging unit, drum unit or photoreceptor drum.

For a drum to transfer the text and toner to the page, it first receives a positive charge from the corona wire. A laser writes over the drum and leaves a negative charge where the text and/or images will appear. Next, the paper is fed by the pickup rollers and receives a stronger negative charge that pulls the toner from the cartridge to the drum onto the paper. When the toner hits the drum, it sticks to the oppositely charged areas to create text and images.

Because the laser writes on the drum for each print, the imaging unit goes through a lot of wear and tear and must be replaced after a certain amount of pages. Near replacement time, the drum unit begins to show signs of wear. If your drum is letting you know it’s time for a new unit, you’ll see black spots and/or lines on the pages and images will be lighter than normal.

Also, some printer manufacturers include drum units on their toner cartridge. This way, every time you replace the toner cartridge, you are replacing the image drum. The duration that the drum lasts really depends on the printer. Some last 10,000 pages while other last 25,000. To get an idea of how long your drum will last, take a look at the manual for the manufacturer’s estimate.