An Insight on working of Toner Cartridges in Printers

Posted by nancypetrson on September 14th, 2019

A toner cartridge, also known as laser toner, is the most important component of a laser printer. These toner cartridges contain toner powder which is made up of a fine and dry mixture of plastic particles, carbon, black or other coloring agents that draws the actual image on the paper. The toner is then transferred to paper via an electrostatically charged drum unit, and further fused onto the paper by heated rollers during the printing process.  The two ingredients of toner, plastic and pigment, each have a simple role in the printing process. For example the pigment provides the color, while the plastic allows the pigment to stick to the paper as soon as the plastic is heated. This melting process binds firmly to the paper fibers, resisting smudges and bleeding, providing an even, vivid tone that helps text appear sharp on paper.

COMPONENTS OF TONER CATRIDGES

Toner hopper: This is the small container which houses the toner.

Seal: A removable strip which prevents toner from spilling before installation.

Doctor blade: It helps in controlling the amount of toner distributed to the developer.

Developer: Developer transfers toner to the OPC (Organic photo-conductor) drum.

Waste bin: It collects residual toner wiped from the OPC drum.

Wiper blade: It wipes away all the residual toner applied to the page.

Primary charge roller (PCR): It applies a uniform negative to the OPC drum prior to laser-writing and also erases the laser images.

OPC Drum: It holds an electrostatic image and transfers toner onto the paper.

Drum shutter: It protects the drum from light when outside the machine and retracts the drum into the printer.

Low-end to mid-range laser printers typically consist two consumable parts: the toner cartridge itself (which has a typical life of 2,000 pages) and the other is drum unit (which has a typical life of 40,000 pages) like the model HP 12A in HP Laser Toner Cartridges. Some toner cartridges also incorporate the drum unit in the design, while both drum and cartridge are replaced simultaneously. However, cost of a cartridge is higher than a toner-only cartridge, although separate drum replacement is generally avoided. Toner cartridges have the same function as they have in ink cartridges used by inkjet printers.

Drum units, like the model Brother DR-2255 in Brother Laser Toner Cartridges, are complex pieces of equipment and this is where the printing mostly and commonly happens. Inside the drum unit the photo-sensitive drum and the corona wire are there.

A laser writes the image or text onto the drum and alters the electric charge wherever and whenever it makes any contact. The drum is then rolled through the toner which is picked up by the charged portions of the imaging drum. Finally, toner is transferred to the paper using heat and pressure. These Brother Laser Toner Cartridges can print an estimated of 1200 pages when it is toner-only cartridge. If it uses drum unit in it then it can print an estimate of 12 000 pages. That means the need to replace the drum unit will arrive after replacing about 10 toner cartridges.

Printer brands like HP and Brother are typical examples of how different brands incorporate both toner cartridges and drum units into their products. For example, HP laser printers generally have the HP Laser Toner Cartridges and drum unit combined as one unit, whereas Brother’s laser printers employ a separate toner cartridge and drum unit. Printers with separate drum units generally last longer than a toner cartridge, so the need to replace the toner arises around 3-4 times.