The image drum
The image drum is the heart of the laser printer or photocopier. It transfers the print image consisting of toner to the paper. Some manufacturers call image drums also OPC, image unit, drum, drum or imaging unit. A dirty or worn drum reduces the print quality of a laser printer very extremely.
Toner and drum are often confused.
For laser printing, toner is applied to the paper using one or more image drums .
Many smaller or cheaper printers use toner cartridges that also contain a toner cartridge (often in the HP LaserJet series). These toner cartridges are called "Kombipatrone". The drum is replaced automatically with each change of toner.
Larger and more professional devices use image drums in addition to the toner cartridges, which can be exchanged separately.
What makes the image drum?
The drum is a 1 to 2 millimeter thick aluminum tube which is minimally longer (or wider, as you can see) than the maximum print width. The image drum is electrically charged by means of focussed light-emitting diodes, by means of a laser beam or by means of an exposure projected by a lens.
The toner particles rotate on the toner roller and are attracted by the image drum and transferred to the paper. There, the toner particles are later fixed with the fixing unit (also called fuser) by heat and pressure. After being transferred to the paper, the drum is again discharged through an extinguishing corona which is operated with an alternating voltage, and any toner residues are removed by a wiper (wiper).
How often do you have to change image drums?
Over time, the coating of the image drum loses its photoelectric properties and suffers from mechanical stress, for example by contact with paper. In particular, inferior, particularly thin paper can leave residues on the image drum. Similarly, toner residues lead to a poor print image.
For drums, there are three distinctive distinctions:
- Image drum which is part of the toner cartridge (one-way drum - life span up to 5,000 pages)
- Interchangeable drums (semi-permanent drum - life span approx. 20,000 and 25,000 pages)
- Permanent image drums (permanent drum - life of up to 500,000 pages)
A change of the drum unit should be considered in particular when:
- the printer asks for a new image drum;
- the prints have vertical streaks and repeating artifacts.
In the case of the semi-permanent drums, it can be said that a drum is also required after about four to five toner changes.
Drum in a combination cartridge (toner and drum combined).
See the image: An HP toner cartridge with an integrated image drum. The image drum already has first small scratches on the surface due to wear.
How to change an image drum?
First, you should make sure that the drum is really broken or worn out, and not just the toner cartridge is blank.
If it is ensured that the drum is defective or worn out, you can simply open the door behind the toner. Depending on the device type or device configuration, the drum behind the toner or, as with Konica Minolta, is often found under the toners.
In this case, care must be taken to determine the special features of the equipment manufacturer when changing the drum. In general, however, it can be said that a lot of heat is generated during printing, and that after the last printing a certain time has elapsed before the drum can be changed.
When installing the new drum it is important to ensure that the new drum is inserted as quickly as possible into the unit and is not exposed to the sun. It is best to check first how the old drum is removed and whether the unit must be switched off.
How many drums does my printer need?
In the case of smaller, more cost-effective printers, the drum, as mentioned above, is contained directly in the toner cartridge and need not be considered further. Larger or more professional devices require either one drum or one drum per color (black, cyan, magenta, yellow) depending on the design.
In individual cases, this should be checked in the device manual. On our website you will see an overview of the articles available for your device - which in most cases is already available.
Can the image drum be cleaned?
We strongly recommend that you do not touch the Image Drum at all. Frequently, a soiling on the drum can also be detected before the drum itself is removed at all. Please remember that an image drum is extremely sensitive and should not come into contact with any liquids, except for cleaning alcohol.