Whant to buy Hp 88 Printhead - HP OfficeJet Pro k550 Printer

https://www.google.com/search?q=printhead+for+HP+C309&rlz=1C5CHFA_enUS831US831&oq=printhead+for+HP+C309&aqs=chrome..69i57j0l4.1623j0j7&sourceid=chrome&ie=UTF-8

HP88 CARTRIDGE RECOGNITION FAILURES/CAUSES:

The failure to recognize an ink cartridge(s) could either be a possible Cartridge connectivity, PRINTHEAD* connectivity or an end-of-life PRINTHEAD issue.

We suggest you remove all the ink cartridges and thoroughly clean BOTH PRINTHEADS manually along with cartridge chip contact surfaces (located on bottom-rear side of each ink cartridge). Clean all electrical contacts, including those inside the printer which mate to the PRINTHEADS. Reinstall both PRINTHEADS and cartridges and retest. You may refer to HP's 'manual' cleaning procedures here:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=125&prodSeriesId=2511747&prodTypeId=18972&objectID=c00844045

Ensure an "expired ink cartridge" alert state is not causing the issue, refer to this page on how to check & bypass: http://inkjet411.com/?page_id=1384

---- If you observe an "Expired xxxx ink cartridge" alert or message, this error may be bypassed by performing the following:
a. Press and HOLD the Power button.
b. Press Resume button 3 times.
c. Release the Power button

If the cartridge was refilled (i.e. at Costco or Fry's Electronics), following HP 88 cartridge chip replacement and complete cartridge/printhead/printer manual electrical contact cleaning, the cartridge alert message(s) continue, then you may have a damaged PRINTHEAD* (there are two printheads inside the printer) which may require re-priming or replacement depending on problem symptoms.

* The HP 88 ink-series printer models have two electronic PRINTHEADS (each of these electronic devices are responsible for pulling ink from the ink cartridges and then firing the ink droplets onto the paper) - both PRINTHEADS will eventually fail depending on printed content, printer duty cycle (i.e. typically rated for ~41, 500 printed pages depending on image content & frequency of printing). The average inkjet printer can typically be refilled with ~15 to 20 complete sets of ink cartridges over the life of the printhead, after which, either the Yellow/Black and/or Cyan/Magenta printhead will need to be replaced due to internal electrical failure (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 3rd party PRINTHEAD priming tool, such as this one: http://www.inkowl.com/?p=product&product=5035

For advanced HP printer diagnostics or information on ink refilling services, please visit Inkjet411:
http://www.inkjet411.com

This page explains how to replace a printhead and links to the HP parts store where you can buy the printhead.
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01643079&cc=us&dlc=en&lc=en&product=3795406&tmp_track_link=ot_search

Hello and welcome to FixYa!
In the HP OfficeJet Pro L7780 the printheads are actually separate from the ink cartridges. In your case, it sounds like the black/yellow head has worn out and will need to be replaced. The good news is, this is a user replaceable part. The bad news is, the replacement heads are not cheap. Amazon has the HP 88 Black/Yellow printhead listed currently for about $61.
http://www.amazon.com/HP-Yellow-Officejet-Printhead-Packaging/dp/B000BO9L8M/ref=dp_cp_ob_e_title_0
YouTube has a nice video that explains how to install the printheads here:
http://www.youtube.com/watch?v=8Zl0LUxBSvg
I hope this helps!

Take it out and clean the contacts. Put it back in and see if the problem's gone. If not, buy new printhead.

There is a clean prinhead utility in the windows driver.
1. From the printers and faxes window right click on the K5400 icon and select properties.
2. Select the printing preferences then features tab then the services tab.
3. Click clean printheads.

The printer will go through a printhead cleaning process. When its done check the print quality again. If the quality does not improve I would recommend replacing the HP 88 Black and yellow printhead part# C9381A which is user replaceable and comes with install instructions.

You either got a defective printhead or you are using generic inks, HP got real smart and added chemicals to their ink, if the printer doesn't see the right chemical makeup it will give that error and you need to flush the printhead and the pump and hoses with HP ink or the error will stay.

The problem is in the print head.It's clogged or damaged.You need to replace it.It's part number is C9381A - HP #88 Printhead - Black and Yellow

i order the 8 jan 2010 2 print heads No : 88 (ref hp c9381a for black/yellow and ref hp c9382a for magenta/cyan) and i receive it after 4 days.

Normal 0 Driver could be corrupt.
Disconnect the printer or at least be sure it is turned off. I'd do both and reinstall the CD software program that came with the printer. When the software program asks you to connect the printer to the USB port, do so and it should again work properly.
Hope this helps. Bud