Before we get started on the inner workings of an HP toner cartridge lets clarify what toner is. As most of us know, toner is the powder substance which laser printers and photocopiers use to create the image of your page onto paper. In its earliest form it was simply called carbon powder but was later changed to toner when carbon was mixed with a polymer to improve print quality.

Right with that out of the way, how does an HP toner cartridge work then?

To start off with, the innards of an HP toner cartridge are housed in a rigid plastic housing which sometimes uses graphite for strengthening. Inside the toner cartridge there are also many different components used as laser printing is quite a technical process.

Toner cartridge designs vary but generally the following components are found within one.

Toner Hopper

This is a small container which is built into the casing of an HP toner cartridge. The job of the toner hopper is to house and store the toner formulation which is used for printing. It’s also noteworthy that the bigger the toner hopper, the more printing the toner cartridge can produce.

Toner Cartridge Roller

The roller sits on the outside of the toner cartridge and can usually be seen on the bottom of the cartridge. Its job is to transfer toner to a component called the drum unit. It is actually the drum unit which creates the image of your page and uses the toner to print with.

Toner cartridge rollers are made of metal and can sometimes be called developers. They vary in their method of application of toner to the roller. Some use magnetic toner which has magnetite in it others use different methods of particle attraction.

Doctor Blade

The doctor blade attaches to the toner cartridges roller. Its job is to ensure even distribution of toner formulation onto the HP’s toner cartridge roller.

Wiper Blade

The wiper blade sits close to the toner cartridge roller and doctor blade. Its job it to wipe off any residual toner left over by the drum unit from the page. Additionally, the wiper blade remains in constant contact with the drum unit.

Waste Toner Collection Unit

This unit is where the left over toner from the wiper blade is stored. These units can be sold individually but are sometimes combined into the body of an HP toner cartridge.

Toner Cartridge Seal

The seal is the removable protecting strip which prevents toner from spilling out of the HP toner cartridge during transit.

What about the drum unit?

Depending on your printer, drum units are either combined into one unit with the HP toner cartridge or sold separately. Some manufactures call these combined units imaging units.

As we have already said, the drum unit or photo conductor unit creates the image of your page to be printed. Whether it is sold separately or combined into one printing unit the principle or fundamentals of it remain the same.

There are two main components in drum units called a primary charge roller and organic photo conductor unit. They are complicated units which use statically charged negative electricity amongst other things to create the image of your page. They use this static electricity to attract toner particles onto the page which is then applied by the organic photo conductor unit. This unit is a multi-film layered aluminium drum which has been manufactured to be perfectly cylindrical. The quality of an HP toner cartridges printing is directly affected by the cylindrical precision by which the photoconductor units have been manufactured.