User-replacement of HP9000 Printheads?
Posted: Wednesday, August 19, 2009
by Matthew Theobald
Exhibition display solutions
If you are experiencing problems with the printheads on your HP9000 you may find home useful information here
Although we have found this printer to produce a good quality print and to have been reliable, there is a question mark over the longevity of the printheads and also the high cost of replacing them. You will find, in this article, my experiences dealing with these issues and I hope you will find some inspiration for dealing with your own problems.
When routinely printing the IQ test print to confirm that the quality of print from each head was acceptable, we noticed that the L Magenta swatch had a scratchy appearance. We were advised that this was an indication of a head that was wearing out and that it would need replacing soon.
Just in case the engineer had been mistaken we decided to give the head a physical clean using a fine cloth and some wiper fluid. Repeating this a number of times resulted in the print quality returning to its original quality.
Over 2-3 days, however, the IQ print became somewhat 'scratchy' again - although the majority of prints were of an acceptable quality the problem was particularly apparent on large regions of single colour using the light magenta.
Having persevered with this cleaning routine for a few months, the head was causing so many reprints that it was decided to bite the bullet and pay for the head to be replaced. We were quoted a cost of 1600 + call-out charge for this. A maintenance engineer was arranged to attend on the Tuesday following the weekend to double-check that the head needed replacing.
In order to improve the head as much as possible before the engineer came to confirm the need for replacement we switched the printer off - this seats the printheads in a bath of ink and is recommended in order to soften any congealed ink and aid cleaning.
When Monday arrived we switched the printer back on and gave the heads a purge in anticipation of the engineer arriving the next day.
When the engineer arrived he ran the IQ test to ascertain the state of the print quality and found that all 6 heads were printing scratchily. The heads did seem to recover a little after a number of strong purges but it was not consistent and still did not produce a useable print quality.
After a significant amount of further cleaning it was decided that we would replace the Magenta and Light Magenta Head under a scheme run by HP for out of warranty machines where they agree to sort out any problem (including changing up to 2 heads) for a 1 off charge of 1000 (Im not aware if they are still running this scheme)
When a second engineer came to change the heads he noticed that there was an air leak into the ink reservoir. Once this had been fixed and the heads cleaned a number of times, the prints being produced were of an acceptable quality and the IQ prints appeared to be improving a little each time they were printed.
We were concerned, however, that once the engineer had gone, if the heads deteriorated we would have missed our opportunity to have them replaced as part of the HP scheme. We had some concerns that if any of the printheads deteriorated after the engineer had signed off the job that we would have missed the opportunity to have them replaced as part of the HP deal, so we asked him to leave the heads with us.
Almost inevitably, the day following the engineers visit, the light magenta and magenta heads deteriorated significantly. The earliest that the engineer could return was in three days so we decided to investigate replacing the heads ourselves.
Parking the head and switching of the machine we then removed all the covers on that side of the printer to allow easy access. Next the printhead assembly covers were removed to allow access to the printhead themselves. Next using a scalpel we scratched marks into the head fixing plate to mark the current position of the head. Using the caps supplied with the new printhead, seal off the ink flow and remove the connector for the electrical feed. Take a small socket driver and undo the screws which secure the head to the fixing plate.
We then removed the printhead from the storage packet and carefully placed onto the head fixing plate, lining it up with the marks previously made. Next connect up the ink supply tube as before and press-on the electrical connector. Replace covers and run the ink system purge routine in the maintenance menu to fill the printhead with ink and run the head alignment routines to fine tune the alignment.
We did this with both heads and they are working fine. All the other heads have improved with use (and regular cleaning) and are printing well.
We have since been made aware that the use of an ultrasonic cleaner can return the heads to a good condition when they have been clogged with ink.
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Matt Theobald has worked in the exhibition industry for 21 years, designing, building and producing the graphics for exhibition stands, popup displays and bannerstands. He is co-director of Exhibition Display Solutions Ltd in the Thames Valley. http://www.exdisplay.co.uk
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