Cyan head dropping ink

[ahmedsamy]

Suddenly the Cyan printhead in my Design jet 9000 had large gaps of white area in the test print, I run 3 strong cleaning cycles, it started printing properly then it started to drop ink on the media.
Same ink, same media settings, wipers and capping station are both clean and working properly, print head is perfectly clean, no dust or dirt on the printing surface.

Any idea what is happening?

Ahmed Samy

 

[Tin Ho]

Your cartridge may be defective. It is causing ink to leak out of the print head. The leak is probably very slow. It forms a pool first and the pool of ink blocks some nozzles so you see white streaks sometimes. When the pool of ink gets bigger it drips off and you see ink drops on paper. Been there on some Canon printers.

 

[ahmedsamy]

Many thanks Tin, what is confusing is that the problem occurred while using the same cartridge, even though, does a defective cartridge can cause extreme pressure that makes the ink leak?

 

[Tin Ho]

I am not very familiar with HP ink cartridges for the designjet 9000. They are huge 1 liter cartridges. I wish I had one for printing photos. I used to play with two older models that I don't remember their model names. They have an internal mechanism to regulate the ink flow out of each cartridge. There should be a vent somewhere on the cartridge. It should remain unblocked. It keeps internal pressure at where it is supposed to be. At a couple of hundred bucks each it is hard to just replace it. Just take it out and see if you can find anything obvious such as crack or damage. Try another cyan cartridge you can prove that the cartridge is indeed defective.

 

[ahmedsamy]

Hi Tin, I have received this comment which I think logical although quite expensive.
"Hello Ahmed,
every printhead has a "non-wet-coating" to keep the ink aerosol away from the nozzle outlets of the head. If this coating is destructed, during printing the ink is building up at the nozzle surface and also directly infront of the nozzle outlets. From that moment on the nozzle isn't firing the ink on the print media but in the drop. With every ink shot the drop becomes larger and larger until it is falling down on the substrate. In most cases the drop is falling when the head carriage changes its direction for moving back.
So the solution for you will be to change the head.
Best regards
Christoph"

 

[ahmedsamy]

Dear All,

I finally found out the cause of the problem, it's a tiny crack on the cyan ink tube. (check attached picture) http://www.imagebam.com/image/81c3ca135792368

 

[websnail]

That'd ruin your whole day...

I guess worth adding "Look for signs of ink leakage" to the troubleshooting list is in order..

Thanks for reporting back...