Dried out nozzles

The biggest problem with refilling some HP, Canon and Lexmark printers is a dried out cartridge. If an HP cartridge is left empty for more then 30 minutes, the ink will dry and clog the small holes in the print head. When refilled, the results will be streaked or banded output.

If you don't plan to refill your cartridge right away, put it in a zip lock bag with a damp cloth until you can get to it.

If the nozzles are blocked or dried out you will need to dissolve the dried ink. An inkjet nozzle has a diameter of about 45 microns which is about 1/2 the width of a human hair. 

Soaking & Flushing

Flushing with hot cleaning solution through the print head is usually the best way to clear stubborn blockages. There is equipment available to do this with price tags ranging from $250 up to $15,000 or more. For most people, soaking the print head in a distilled water/alcohol
or ammonia solution or one of the proprietary solutions (Cartridge Flush) specifically designed to clear print heads. Soak the print head for about 10 minutes to overnight depending on the degree of blockage. It has also been reported that you can clean the print head with an 
electronic toothbrush and cleaning solution for about 20 seconds with excellent results. 

Steam Cleaning

Steam vaporizers are available from drug stores or pharmacies. They are perfect for cleaning print head nozzles since steam is released from a small vent about the same size as the print head. Steam for about 30 seconds to five minutes.

Printout is Terrible

If you can see ink at the print head when you dab it with a tissue but still it presents a terrible printout there may be a few reasons.

The resistors that comprise the print head are burned out. Discard the cartridge. You will not be able to refill it If the cartridge uses internal pressure, it might be over or under pressurizes. Remove or add pressure accordingly with the air pressure bottle. You may have to let the cartridge sit for a few hours until the internal pressure stabilizes on its own. 

Removable Print Heads 

If your printer has a removable print head such as the BC-21e simply fill the chamber over the print head with boiling distilled water and sit it on a clean cloth to drain. Prime the print head by running the cleaning routine a few times.

Air in the Cartridge

If you have done everything and still the cartridge won't print, there is a chance that air is trapped over the print head. If you have filled the cartridge too fast it may be full of foam. Foam is air. Let the cartridge sit overnight and the problem may clear up on its own. 

Using Centrifugal Force to Eliminate Air Pockets

Some sponge filled cartridges will develop air pockets at the bottom of the cartridge which can block the ink flow.

HP and Epson color cartridges are notorious for this problem.

Here is one solution. Wrap the cartridge in a towel or cloth and then put it in a plastic bag to prevent a mess. Hold it in your hand with the print head (HP) or exit port (Epson) facing down. Extend your arm and swing the cartridge down towards the floor rapidly, like you were going to throw it. Snapping your wrist seems to help. Do this a few times. Remove the cloth and you should see a spot of ink from each of the chambers. If not, repeat the procedure.

Using Pressure to Prime Print Heads

Many cartridges such as the Canon BC-20 may need to be primed before they start working. To prime the cartridge obtain a small piece of fish tank tubing. Put the tubing in the top central vent hole and blow through until ink comes out of the print head. This procedure can be used on other cartridges with equal success.

Using Suction to Prime Print Heads

Some cartridges that do not respond to any other method will start working after this procedure. Obtain a grommet from a BJI-642 cartridge. Attach the grommet to a syringe with a hot glue gun. The grommet fits nicely over most tri-color cartridge print heads. 

Repairing Cracked Maze Hole on HP 51629A Cartridges

These cartridges tend to leak from the bottom maze plate on the bottom of the cartridge. The maze plate is extremely brittle and can develop cracks. Use a thin smear of waterproof silicon gel like the sealer used to fix aquariums. Be careful not to seal over the maze hole. 

Clearing Blocked Maze Holes

You must remove all the ink from the cartridge before doing this. Fill the cartridge with very hot solvent. Distilled water and alcohol for the 51626A, Cartridge Flush for the 51629A. Sit the cartridge in a dish of solvent overnight.

Dried out Internal Sponge

Inject 15 ml of pure ethanol into the cartridge. Then withdraw as much as possible. The ethanol will evaporate very quickly so you might not get much back out. Re-ink the cartridge normally.

Burned Out Cartridges

Many cartridges with internal print heads use electrical resistors to control the current to each nozzle. If the cartridge is allowed to "dry fire" too many times the tiny resistors will burn out resulting in low quality output, color distortion or weak printing. 

The ink actually acts as a cooling agent to keep the resistors from burning up. If the cartridge goes empty and printing continues, overheating occurs. If left too long this can burn out the cartridge. Each time this overheating occurs the life of the cartridge is shortened. 

The solution, of course, is to buy a new cartridge.

Contaminated Colors

If there is air in any of the nozzles, ink from one of the other nozzles can, by capillary action, be drawn across to the empty nozzle and contaminate the chamber. Also overfilling certain cartridges can cause cross chamber contamination. If the contamination is severe the
cartridge may no be able to be repaired. In the case of slight contamination you can try letting the cartridge sit on a damp cloth overnight. The contaminated ink will be drawn out of the print head by capillary action. Run some cleaning routines to prime the cartridge.

For serious contamination you'll have to remove the internal sponges and wash them in alcohol followed by hot distilled water, then allow to dry thoroughly before replacing them. Wash out the cartridge cavity with boiling hot distilled water. Fill the cartridge with boiling water and sit it print head down in a small container to allow the old ink to seep out through the print head. 

Tips for Refilling Color Cartridges

Always inject the ink very SLOWLY so that it doesn't froth up or cause air locks in the cartridge. Air locks are trouble in any cartridge but particularly so in tri-color cartridges since they can cause ink to migrate from one nozzle into another. If the cartridge is full of froth let it sit overnight.

Toothpick Test

Before refilling any tri color cartridge it's a good idea to use three toothpicks and insert one into each fill hole to check the color of ink in the chamber. 

Color Cartridge Prints Green Instead of Black

Some printers that hold only one cartridge use the color cartridge to print black. Examples are Lexmark 1000, HP 400/600 and Canon 210/240/260. When the three colors are combined they should
produce black. This is called composite black. Many times the black will have a greenish tint to it. Make sure that you use the MATCHED color set for refilling these cartridges. Ink manufacturers like Repeat-O-Type have specially formulated the three colors to produce black when combined. You can also try adding about 10% water to the yellow ink. This will produce a blacker black but a trade-off could be a slight color shift when printing photos.