Hp inks seem to be variable in print quality. Two cartridges (in the same batch - a twin pack of HP 344) gave consistantly poor prints - the colours were drab and lack-lustre. I have used upwards of 100 cartridges in the past few years and never had such poor quality prints. Has anyone an explanation for this?

Ebay is your best shot to get a printhead. Hp does not seem to stock the printheads in North America.

For poor printing problems I suggest you run the Tap 10 diagnostic print test (see link to video below).
If the new (or refilled/reman/compatible) HP 56, 57 or 58 ink cartridge refuses to print black/color and/or function at all (i.e. blinking ink light on Deskjet 5000 series printer) or fails to complete the printer alignment following cartridge installation, then the ink cartridge either has a connectivity issue with the flexible printed circuit cable (inside unit where cartridge mates with cable), the rear cartridge contacts or cable contacts are dirty with ink residue, or the cartridge is suffering from marginal internal electrical performance. It is suggested you perform the TAP 43 (and TAP 10) DIAGNOSTIC PRINTER TEST to evaluate the ink cartridges electrical performance. Visit Inkjet411 support site to see instructional video: http://inkjet411.com/?page_id=2358
NOTE: For the HP Deskjet 5000 series printer models, when you get an HP 56, 57 or 58 integrated ink cartridge refilled (i.e. currently offered at Costco or Frys today) or if you buy a remanufactured/compatible HP ink cartridge, the ink levels are not initially reset. However, continuing to use an ink cartridge which displays LOW INK alerts is permitted by the printer, simply select OK, CONTINUE or DISMISS when these alerts are observed. Now, it is possible to reset the ink levels by performing the procedure outlined on Inkjet411's site: http://inkjet411.com/?page_id=1915
To clean the HP 56, 57 or 58 ink cartridges please visit the Inkjet411 site which provides recommendations on how to clean the electrical contacts, flex driver cables and how to perform a hot water flush of the nozzle plate (refer to video): http://inkjet411.com/?page_id=1519

It is a problem using refilled toner cartridges, especially in colour machines. Mono (Black) printers are usually ok to use a good quality refilled cartridge, but colour machines generally do not like them.

Have you tried to print a Configuration page from the control panel <Information> menu?

nope...... the problem as you rightly poit out is the cartridges, most refills are poor quality and dont last, but the real ones are expensive but very rarely cause issues. If one colour is dodgy the entire colour process fails, print a square of each colour to determine which colour cart is the issue and complain to seller, 99.9% of print quality issues with these HP's is due to non gen toner....not much you can do, expensive is colour printer fullstop.

it sounds as though you haven't use this in a while and the ink has dried in the head/jets. try cleaning the nozles and get new ink cartridges.
start>printer & faxes>properties>print preferences>maintenance tab (if you have one) and look for head cleaning.

I have no magenta trying second cartridge still same problem

Hi, have you tried another cartridge? Sometimes if a cartridge has been sitting around for a while, they become blocked with dry ink and print quality gets poor.

Brand new colour ink cartidge was faulty and has had to be replaced.

Hi Manavoc,

I will explain you the cause for it.

It prints in yellow first and then override with black for better quality. This is the reason your color ink gets empty.

http://h10025.www1.hp.com/ewfrf/wc/genericDocument?docname=c00308490&cc=us&dlc=en&lc=en&jumpid=reg_R1002_USEN

Have a great day!

Issue The printer is working, but the colors in the printed output are not the expected colors. The output may look as if only one color has printed, or as if a color has not printed, or as if the wrong colors have been printed. Solution Complete the following steps to resolve this issue. Step one: Check ink levels If the print defect is minor, it might be caused by reserve mode operation. When the printer runs out of some colors, it can continue printing using remaining inks, but print quality may be affected. If cyan, magenta, or yellow is out, the printer can print only in grayscale.
NOTE: HP cannot guarantee the quality or reliability of non-HP ink. If ink cartridges have been refilled, try replacing them with genuine HP ink cartridges. Replace any empty print cartridges. To access the ink level gauge, follow these steps.

1. Press Setup .
2. Press to select Tools , then press OK .
3. Select Display Ink Gauge and press OK . The ink levels are displayed. Figure 1: Ink levels
   • Each icon corresponds to the cartridge that is the color of the icon. The icons are also in the same order, from left to right, as the cartridges in the printer.
   • If an icon is empty, the corresponding cartridge may need to be replaced soon.
   • The ink levels in non-HP, refilled, and remanufactured cartridges cannot be read by the printer. Instead of an icon, a question mark is displayed for these cartridges. HP cannot guarantee the quality or reliability of non-HP ink. Printer service or repairs required as a result of printer failure or damage attributable to the use of non-HP ink will not be covered under warranty.

Step two: Calibrate the color If the cartridges have not been refilled and none are empty, try calibrating the color.

1. Open the printer Toolbox :
   1. Open HP Solution Center (click Start , then All Programs , then HP , then HP Solution Center ).
   2. If you have more than one printer installed, make sure to select the correct printer tab in HP Solution Center .
   3. Click Settings .
   4. Click Print Settings .
   5. Click Printer Toolbox .
2. On the Device Services tab, click Calibrate Color , then follow the onscreen instructions. The procedure takes about two minutes and requires two sheets of paper.

Step three: Clean the printhead If the steps above did not help, clean the printhead.

1. Open the All-in-One Toolbox :
   1. Open HP Solution Center (click Start , click All Programs , click HP , and then click HP Solution Center ).
   2. If you have more than one All-in-One installed, make sure to select the correct All-in-One tab in HP Solution Center .
   3. Click Settings .
   4. Click Print Settings .
   5. Click Printer Toolbox .
2. On the Device Services tab, click Clean the Print Cartridges , and then follow the onscreen instructions. Three levels of cleaning are available.

Step four: Contact HP If the error still occurs, click the link at the bottom of this page to contact HP.
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00707165&lc=en&cc=us&dlc=en&product=1153481&rule=45772