Technical information

242
242
rated for 30, 000+ printed pages depending on image content & frequency of printing). The average
inkjet printer can typically be refilled with ~20+ complete sets of ink cartridges over the life of the
printhead (warranted for only 650ml of ink however, or approximately 9 cartridge refills), after which,
either the Yellow/Black and/or Cyan/Magenta printhead may need to be replaced (available at HP.com).
Refer to video on how the HP PRINTHEAD functions: http://inkjet411.com/?page_id=2054
When the PRINTHEAD electronically fails typically the printer will provide an alert message when this
happens, but if a printhead has suffered a deprime (i.e. loss of ink/pressure which results in no printing
of color), it is possible to recover the system using a 3
rd
party PRINTHEAD priming tool, such as this one:
http://www.inkowl.com/?p=product&product=5035
We apologize if this HP 8500/8500A 'workflow caveat' caused you any confusion.
For any additional questions please contact us directly: [e-mail]
-Thank you
HP OFFICEJET PRO 8500/8500A (HP 940s) – PRINTHEAD FAILURE MESSAGE
Regarding your inquiry over HP940 refilled ink cartridges and the reported printer error message on
your HP OJPRO 8500 printer ( “The Following Printhead Appears to be Missing or Damaged” / “The
Following Printhead has a Problem”), please note this type of problem is usually severe in nature and is
typically caused by failed micro-electronics within either of the two (2) PRINTHEAD assemblies.
A PRINTHEAD "missing" / "damaged" / "problem" error has nothing to do with the HP 940 refilled ink
cartridges since these are just plastic tanks which hold ink - all ink formulations have been fully tested
for compatibility with all HP printer systems. It has been our observation that HP OJPRO 8500/8500A
printhead life does vary widely from printer to printer (anywhere from 1000 pages to 20,000+ pages!!).
The timing of a printer/printhead failure is merely coincidental with with respect to the use of refilled
ink cartridges. Each PRINTHEAD is a complex electronic ink-firing assembly which sits directly behind the
ink cartridges during the printer idle state; the cartridges plug into and feed ink to both the Yellow/Black
PRINTHEAD and Cyan/Magenta PRINTHEAD.*
A. To help resolve the current printer alert state, we suggest you refer to the lower half of the
following Inkjet411 support page. Remove all four (4) ink cartridges and both PRINTHEADs from
the printer. Thoroughly clean the electrical contacts on one (or both) PRINTHEAD assemblies.
Reinstall PRINTHEAD(s) and ink cartridges, and retest. http://inkjet411.com/?page_id=1457
NOTE: Here are HP’s s teps for resolving, removing/replacing and cleaning th e PRINTHEADs:
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c01817398