Inkjet printers are certainly a great invention however nowadays they print at such high resolutions that they are becoming a problem. As printers start to print at super high resolutions the size of the small nozzles which spit the ink out are becoming so minuscule that they tend to clog easily.
When I say minuscule I mean smaller than the diameter of a human hair, YES very small indeed. The actual problem causing the clogging is the ink drying on the surface of the printhead. To prevent this from occurring the printers use a thing called a “purge pump” which every now and then sucks ink from the cartridges through the printhead and out into what’s known as a “Waste Pad”.
If you’ve ever heard your printer whizzing around and making weird noises when you want to print then that is most likely the printer doing an auto nozzle clean. All printers also have the option to do a manual nozzle clean as well. This is usually found under the “Maintenance tab” and is labelled as “Nozzle Clean”.
The purge pump is also used to prime new cartridges when they are installed. Under ideal conditions when a new cartridge is inserted the pump sucks the ink from the cartridge through the printhead and spits any excess ink onto the waste pad below. In older printers sometimes the pump is weak and it isn’t able to prime the new cartridges correctly when they are being replaced.
What are the main causes of printhead clogging
There are many reasons for an inkjet printer head to become clogged. This is also the main reason that the majority of inkjet printers end up at the tip. The following are the main reasons for a printer head to become clogged.
- Lack of use – If a printer is not used often enough then the same ink sits in and on the surface of the print nozzles. Eventually the ink dries and nothing can get through the tiny nozzle openings no matter what you do.
- Extremely low grade ink – Some generic cartridges use a very low grade ink with very poor ability to resist drying. What this means is that the ink dries faster than it should on and in the printhead and once again causes the nozzles to become clogged.
- Faulty Purge Pump – As explained previously the purge pump is used to prime the cartridges when they are installed. If the pump is not working correctly then it doesn’t have the ability to suck the ink from the cartridge and into the printhead.
- Cartridge not breathing – Ideally when a new cartridge is installed it creates a vacuum seal with the printer which in turn enables the purge pump to effectively suck the ink to the printhead. Most cartridges have a “breather tape” on the top of the cartridge which when removed releases the vacuum pressure in the cartridge itself and allows the purge pump to work correctly.
- Purge Pump seal damaged – The purge pump has two seals. One around the black nozzle and one larger one around the colours. If these seals become damaged or compromised in any way then once again the vacuum seal is compromised and the purge pump cannot work correctly.
What are the signs of a clogged printhead ?
The signs of a clogged printhead are varied ranging from nothing printing at all and a blank page coming out the printer instead of what you tried to print. Sometimes the result is simply one colour missing which often shows up as incorrect colouring. An example of this would be a scene with the sky being yellow instead of blue or a purple flower coming out a reddish colour.
Another tell tale sign of a clogged printhead is horizontal white lines in the print. This is a very clear indication that a number of individual nozzles are completely blocked and no ink is coming out of them. Usually if the purge pump is working correctly a simple nozzle clean from the printers menu will fix this problem.
How to avoid a clogged printhead
- As stated previously the best way to avoid a clogged printhead is simply to print regularly. By doing this the ink is continuously moving and it doesn’t have time to solidify and clog the tiny nozzles. A recommended amount of printing is at least two full colour pages a week, any less than this and you may encounter problems.
- Change the cartridges when the printer tells you to! This is another cause of clogging as people keep printing until the cartridges are dry and once they are dry the purge pump starts sucking air into the printhead which rapidly dries any ink that is present in and on the surface of the printhead.
- Make sure that the breather tape on the top of the cartridges are fully removed before inserting them into the printer. If they are left on accidentally then the purge pump only pulls air through into the head which accelerates the drying of any residual ink which is still in the printhead.
Cleaning a clogged printhead
Once a printhead or printer nozzles are clogged there are only two solutions to unblock them. The first is to run a nozzle clean or a deep clean from the printer’s maintenance utility on the actual printer menu. This activates the purge pump which then tries to suck any residual ink that is inside the nozzles out through the tiny openings leaving them clear and free to print again.
The problem with this is that a majority of the time the ink has sat in the nozzles for too long and it has dried quite hard which makes it difficult to shift. Often it is only worth doing a maximum of two nozzle cleans as the process uses a load of ink and it won’t take long for the cartridges to empty.
If the previous method did not work and there is no improvement then the only other fix is to do a manual clean. Depending on what printer you have will determine what method you use. The older Canon printers use a removable head so these can easily be taken out and the head can simply be washed under the sink using hot water until all old ink is removed.
Printers that do not have a removable head obviously must be cleaned in situ. This involves using flexible tubing attached to a small syringe, the syringe is filled with a cleaning fluid or often even “Windex” which is pumped into the top of each coloured nozzle a few Ml at a time and then left to soak for up to several hours. The idea of this is to break down the dried ink so that it is easily removed from the printhead surface.
This process often needs to be repeated several times over a period of a few hours before the ink will start to actually break down and begin to come away from the printheads surface. Blotting paper or paper toweling such as is used in most kitchens must be placed under the printhead before the process begins. The best way to visualize this whole process is by watching the video below: