Printer only printing one colour that has changed since cleaning tri colour hp 78?????

[shabbaswoosh]

Genuine CMY print cartridge and black but struggling to get more than one colour printing at any one time.

To start with it was only printing magenta. 

cleaned print heads got a three colour stripe on blot paper but now only printing cyan with the faintest hint of magenta on the test sheet after reinstalling?

ITS AN OLD DESK JET 1220C 

[Bob_Headrick]

The most common issue with HP 78 cartridges (or the similar design 41 and 23 cartridges) is air ingested in the printhead due to cartridges that have been stored for many years.  HP cartridges do have a two year warranty, see the document here for information.   See the date as shown here:

Likely the cartridges you have are years beyond their end of warranty.  There are some ways you may be able to recover these cartridges to print all colors:

• Printhead soak.  Get a teacup and put about 1-2" of very hot (but not boiling) water in it.  Put the cartridge nozzles down (in the same orientation it would have in the printer) in the water and let the cartridge soak for about ten minutes.  After the soak remove the cartridge and gently blot the printhead with a damp tissue.  A working cartridge will have a strong blot of cyan, magenta and yellow.  If all three colors are visible then dry the electrical contacts with a lint free wipe.  A clean dry coffee filter works well for this.  Put the cartridge back in the printer and run a couple of cleaning cycles from the front panel* or toolbox.  If this did not resolve the issue then you can try a more drastic approach as follows:
• Centrifugal force.  Get an old sock that you do not mind ruining.  Put the cartridge in the toe of the sock with the printhead pointing to the toe.  Now go outside to a clear spot, free of obstructions and people.  Swing the sock quickly around your head a half dozen times.  Take the cartridge out of the sock, being careful not to get ink on your fingers or clothing.  Try blotting the printhead on a damp tissue to check if the cartridge is now able to deliver all three colors.  Repeat if necessary.

* To run a cleaning cycle from the front panel do the following:  turn on the printer.  Once the printer is ready press and hold the power button.  While holding the power button press and release the cancel (X) button twice in quick succession, then release the power button.  This will run a cleaning cycle.  A more aggressive cleaning cycle may be run by pressing and releasing the X button twice, then pressing and releasing the formfeed button once (more aggressive) or twice (most aggressive) before releasing the power button.