How do toner cartridges work?

One important and most interesting aspects of laser printers and copiers is the toner. Instead of the printer that dispenses ink, the paper actually “grabs” the toner. The toner itself is not an ink but an electrically charged powder of plastic and pigment.

How does toner work?

The two ingredients toner, plastic and pigment each play a simple role in the printing process.

The pigment provides the color while the plastic leaves the pigment to stick to the paper as the plastic heats and melts.

The melting process gives the laser toner an advantage over ink because it bonds firmly to the paper fibers and resists stains and bleeding.

This also provides a smooth, vivid tone that helps make text appear crisp on the paper.

Another advantage of toners is the cost. Offices typically choose laser printers because the cost of replacing toner cartridges is lower than for inkjet cartridges, and laser printers usually cost only slightly more than inkjet printers.

Anatomy of a toner cartridge

The design of a toner cartridge varies by model and manufacturer, but the following components are common in most toner cartridges.

Toner hopper: The small container that houses the toner

Toner Seal: A removable strip that prevents toner from spilling before and during installation

Scraper blade: Helps to control the exact amount of toner that is distributed to the developer

Developer: Transfers toner to the OPC drum

Dustbin: Collects residual toner that is wiped off the OPC drum

Wiper Blade: It’s main purpose is to wipe away residual toner applied to the page

Primary Charge Roller (PCR): Applies a uniform negative to the OPC drum before laser writing. It also clears the laser image

Organic Photo Conductor Drum (OPC): holds an electrostatic image and transfers toner to the paper

Drum lock: protects the drum from light when it is out of the machine and pulls the drum into the printer

How does the cartridge work?

In most cartridges, toner funnel, developer and drum design are part of the interchangeable cartridge unit.

When an image or text is printed on paper, the printer collects toner from the hopper with the developer.

The developer, consisting of negatively charged magnetic beads attached to a metal roller, moves through the funnel-collecting toner.

The developer collects positively charged toner particles and brushes past the drum assembly.

The electrostatic image on the drum has a stronger negative charge than the beads on the developer, so the toner is drawn from the developer to the drum.

Next, the drum moves over the paper. The paper has an even stronger negative charge than the drum and pulls the toner particles off the drum in the form of the electrostatic image.

Next, the paper is discharged through the Detac corona wire.

At this point, gravity is the only thing that keeps the toner in place. To attach the toner, the paper must pass through the backup rollers, which are heated by internal quartz tube lamps.

The heat melts the plastic in the toner particles, which absorbs the toner into the paper fibers.

Although the molten plastic sticks to the paper, it does not adhere to the heated fuser rollers.

This is possible because the rollers are coated with Teflon, the same material that helps to slip food from non-stick pans.

Color to monochrome printing

Color toner works in much the same way as monochrome toner except the process is repeated for each of the toner colors.

The standard toner colors are cyan (blue), magenta (red), yellow, and black. The black is needed because the three primary colors (red, yellow, and blue) can be combined into any color except black.

The reason is black is not technically a color, but the complete absence of color.

These four toners can produce millions of different shades and hues in varying degrees of saturation and lightness.

This quick guidance through toner cartridges should help them to get a basic understanding of how they work.

The current technology of toner cartridges has enabled laser printers to dominate the office printing market.

Over the next few years, new designs of toner cartridges promise more efficient and cost-effective solutions for office and home printing.