Prolong Cartridge Life

The entire point of refilling cartridges is Economy. HP guys otherwise want us to burn holes into our pockets everytime we need to print even a few pages of text. And this is more so with the HP 802 cartridges since you'd agree with me that the yield of these cartridges are not at all "economical".

One point is clear to all those who have had at least some experience at refilling -- the cost of printing increases drastically as soon as one has to buy a new cartridge.

Refill ink and related stuff hardly cost a fraction of the smallest cartridge available.

So I will try to provide some tips here that, if regularly followed, will lead to drastic increase in cartridge life.

 Before I write those tips, it would be useful to understand how the HP 802 cartridge actually prints.

Below is an image of the printhead from where the ink actually comes out

Now, it may look like just one strip of metal with a circuit, it's actually a lot more than that. Even the ink that we put into the cartridge has to satisfy certain properties so that it can be "used" by the head to print.

The Process

This head is made up of very tiny "heating elements". Whenever a print signal comes to the cartridge (from the golden circuit strip), it heats up the required "element". Now, the ink contained in the sponge has a specific property -- it will vaporise when heated. 

So unsurprisingly, this heat causes the liquid ink to vaporise and get forced out of the head and stick to the paper. And this is the reason we need to allow a few seconds for the ink to dry. Touching the ink at such a nascent stage would cause it to smudge.

Having understood the printing technology (it is sometimes also called Thermal Inkjet, so don't be confused), lets now read a few tips to enhance the cartridge life:

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Do not touch the head with anything that can cause damage to those delicate "heating elements". Once an element is damaged, that part won't be able to print and that is the cause of "missing lines" in printed pages.  

Never touch your fingertip (skin) to the head. Oil and dead skin cells will jam up the head.

Dust can accumulate over the head and cause imperfect output. So it is really worthwhile to clean the head with Isopropyl Alcohol (Medical rubbing spirit that is used to clean your skin before administering an injection) -- just use a soft tissue paper soaked in IPA and clean the head till it is shiny silvery in color

This is not necessary very frequently. Once every 15 days or once every 300-350 prints would suffice.

IPA being an organic solvent also dissolves any dried ink sticking to the head.

WARNING: Do not inhale the IPA fumes or let it come in contact with any part of the body (especially the eyes and the mouth) - it is harmful. Do wash your hands after using IPA.

Since the prints are heat based, do not go on a world record printing spree. The cartridge heats to damage levels if used beyond 50-55 prints continuously. More so if you are printing images.

Continuous printing also increases the wear of the mechanical components inside the printer (being value oriented printers, these printers don't have the endurance of a LASER printer) -- the major reason printer manufacturers quoute the "duty cycle" -- defined as the recommended maximum no. of pages one should print in a month.

Once you're proficient with refilling you would have an approximate idea of how much yield your cartridge is giving. Suppose you get 50 pages on an average after refilling a HP 802 Large Black Cartridge. The idea is to refill it once you've printed approximately 80 % of that amount  (around 40 pages). This is not a strict approximate. Just understand the idea that going blank between a print job is not only frustrating and time consuming but also blank printing seriously damages the head since there is no liquid (ink) to absorb that heat.

Do not let your printer sit idle for long periods of time. Just print some text -- at least one page in 15 days or so otherwise the sponge and head would clog up with dried ink. And you know about sponges - once dried, they become brittle and lose their capacity to retain liquid.

Although it might look like a lot of information to remember and follow on a regular basis but if you are into heavy volume printing, you can actually follow these to get the output equivalent to a laser printer at a fraction of the costs.

To put things into perspective, I've used a HP 802 Small Black cartridge to print more than 2000 pages of output over one year. 

That's pretty cheap and long for a Rs. 400 (USD 7.5) cartridge. Isn't it?