How to tell the difference between a toner cartridge and drum unit

Laser printers have replaced inkjet printers across offices and also for home needs. The reason for its popularity is the better quality and higher speed. Any laser printer that you own has two important components responsible for the print quality: toner cartridge and drum unit. They are both essential for the smooth and efficient functioning of the printer and it is necessary to know the difference between the components and their individual functions.

Depending on the type of laser printer that you own, the toner cartridge and the drum unit might either be separate or integrated into one component. For instance, HP laser printers consist of a combined toner and drum unit whereas a Brother laser printer comes equipped with separate drum unit and toner. Those models that come with both components integrated in one housing case will have better print speed.

There is no clear way to identify whether a particular laser printer will or will not have the components separately. But what is important to remember is that irrespective of whether they are combined or separate, they will continue to perform unique roles. Toner cartridges that come equipped with a drum unit is, on an average, more expensive than its counterparts lacking it.So, what is the difference between the two components?

Electric Charge and Printing

In a laser printer, the toner particles are transferred onto a sheet of paper through a change in electric charge. In fact, the whole process of laser printing works on electric charge, effect of changes in electric charge on toner ink particles and how these changes on the particles results in a page print as the drum rotates.

Toner Cartridge and Drum Unit

While the toner cartridge is the container that is designed to hold the toner powder particles that receive the electric charge, the drum unit is the electrically charged cylinder that contains the image that needs to be transferred to the paper through the electric charge. The printout is churned out after the sheet goes through the “fuser” which bakes the impression permanently onto the paper.

One cannot function without the other – if a drum unit is absent, the toner powder does not get transferred from the cartridge to the paper and without the toner, there is no ink to print out. The two components work together seamlessly to produce the desired results!

Drum Unit Function

One of the most important functions of a drum unit is to attract the toner powder particles through electrostatic polarities and transfer them onto the paper from the toner. The drum receives the electric charge and the image is also drawn here. But, the rest of the drum unit remains neutral. The drum makes use of the principle of electrostatic charge to attract toner powder particles which, in turn, are put on a photosensitive roller within the drum unit. The electrostatic charge draws the image on the drum and this gets transferred onto the paper and printed out. For this reason, a drum unit is also referred to as “imaging unit” or “image drum”.

Replacement of Toner Cartridges and Drum Units

On an average, you will be replacing both the toner cartridge as well as the drum unit during the printer’s lifetime. However, a toner cartridge needs more frequent replacements than the drum unit. Ideally, a drum unit should be replaced after the use of 3 to 4 toners.

People who buy a printer might have preferences on how the components are integrated – individually or together. Some prefer a printer that uses separate toner and drum unit.

Since toners need to be replaced more often, it is easier to remove and replace toners without disturbing the drum unit. On the other hand, many prefer to eliminate the hassle of having to monitor or replace two different components.

When to Replace?

Laser printers come with software programs that are helpful for providing alert messages when a component needs to be changed. However, the error message might not easily point out whether the issue is with the drum unit or the toner. In such a case, and when you know that your laser printer has separate toner and drum unit, you can use certain signs to identify which component is causing the problem and needs to be replaced.

Depending on print quality and function, you can also determine whether the toner is running out or if the problem is with the drum unit. Generally, when the printout comes out lighter than usual, it means that the toner is running low. On the other hand, if the prints are unclear, have spots or streaks or lines on them, then it is the drum unit that is causing the problem. If you have a printer that has the two components housed together, you can assess the print quality and issues to decide when to change the combined housing.

Which Type Works Best?

Depending on the type of printer you use, you might have replaced the drum unit once in a while or never ever had to change it. This lies in the difference in the build of printers. Some laser printers require only replacement of toner cartridges while others require both the drum unit and toner cartridge replacement.

To get a better picture of which type of printer is best in terms of cost effectiveness, it might be worthwhile comparing the operation cost of two different printers: a Brother printer (Model: HL-L2340DW) that uses separate toner and drum unit and a HP Laserjet printer (Model: P1102W) that uses an integrated unit. By comparing print output and replacement cost, the Brother printer was found to be more economical than the HP printer for long-term use. The main reason for this is that separately changing only the toners is less expensive. Also, anybody can easily replace a toner as compared to the complexity and instructions needed to replace a combined unit.

Best Practices

If you invest in a genuine toner and drum unit as and when needed and change it promptly, you can be assured of consistent printer quality over many years. However, genuine cartridges and drum units are not cheap and when you add up the costs, you’ll end up spending as much as the printer’s cost over years.

No matter what printer you own, keep in mind the price of original cartridges and drum unit as well as the replacement cost in the long term. Keep in mind that to save more on printing while using laser printers; you might want to consider using compatible toner cartridges and drum units. Compatible units perform the same function while being at least 70 percent cheaper than the original unit.