How a Laser Printer Works

A Laser Printer is an amazing feat of engineering. They use a Laser Beam to attract toner powder onto a drum which reproduces the image ready to transfer it onto the paper. Then through a series of events the image or toner gets transferred onto a piece of paper. The toner powder then gets baked onto the paper at very high temperatures resulting in a crisp image. Laser Printers are able to print extremely fast and are often used in offices where large amounts of printing is required.

The process a laser printer uses to print

It all starts with either an image or some text being sent from a computer or being scanned by the Laser Printer itself. This image gets transferred to the printers processor which converts the data into an image file suitable for the printer to use.

The processed image is then sent to the printers memory where it is stored ready for printing. While this is happening the drum unit is being charged ready to attract the toner powder in exact duplication as the image waiting to be printed.

How the actual toner gets onto paper

As the feeder pulls the paper from the paper tray, it is negatively charged by another corona wire inside a small drum unit. This makes the paper a lot more attractive to the toner than the photoreceptor drum, causing it to transfer across onto the paper. The paper continues to move along, attracting the toner powder until the full image eventually is transferred onto the paper. The process is almost finished except that the toner powder needs to be bonded to the paper so that it wont come off.

Toner does not dry like printer ink and at this stage it is only stuck to the paper because of the electrostatic charge. So the paper needs to be passed between two rollers known as the fuser unit. The fuser unit quickly heats the surface to around 200 °C which in turn melts the toner onto the page bonding it firmly in place. This is why the paper is quite warm when it first comes out of the printer.

When the page of printing is finished, the photoreceptor drum resets itself with a new positive charge, the excess toner powder is cleaned off and the whole process begins again.

Canon Printhead Cleaning

cleaning a Canon Print HeadCleaning the print head on a Canon printer is a very straight forward task. Up until recently most Canon printers had removable print heads so cleaning was a very straight forward procedure.

If your Canon printer is more than a year old then the following procedure should work for your printer.

1. With your printer turned ON and the cover in the open position wait until the print head carriage moves to the centre of the carriage and stops there.
2. Remove all ink cartridges and carefully place them on a paper towel or similar taking care not to leak ink everywhere.
3. Gently lift the small lever (usually on the left side of the print head) to the vertical position which should unlock the print head from the printer.
4. Remove the print head and place it on paper towling. Take it to the kitchen sink and place it under the sink tap and allow warm water to gently flow through the print head from the top (ink cartridge side) and thoroughly flush out each colour nozzle until all dry ink has been removed.
5. Once fully cleaned allow the print head to dry and then reinstall the print head and inks and run several cleans.
6. Finally print several test pages and make sure that the print quality has returned to normal.

What causes the print head to become blocked?

There are a number of reasons which may contribute to a print head becoming clogged.

1. Infrequent use of the printer.
2. Use of very low grade generic ink cartridges.
3. Constant printing in black and white and very few images.
4. Leaving the printer sitting around for extended periods.
5. Running your inks until they are completely empty and not when prompted.

Best Practices for a healthy print head

1. Print regularly and at least one full page image per week.
2. Use high quality Compatible Ink Cartridges.
3. Don’t set up your printer near a window where it will receive direct sunlight.
4. Remove the print head once a year and flush it out (using the procedure above).
5. If you are running a ciss or continue ink system gently shake each tank on a monthly basis. This stops sediment from forming at the bottom of the tank and flowing into the print head causing blockages.

For more information on ciss and various ink cartridge issues visit the Ink Expresses Blog