Go to the menu of the printer, and select diagnostics.
The following pictures will guide you through the process.
It is also a good idea to check whether or not the print heads are still 'In Warranty'. This is no guarantee for perfect functioning (for instance, they could just be dirty) but a printhead that is 'Out of Warranty' will almost certainly cause problems. You can check the warranty status by selecting 'Ink' from the main menu (icon with two droplets), then 'Printhead information'. For each of the print heads, check the warranty status. This is listed at the bottom of the screen, so you will have to scroll down to see it.
When new ordered printer heads arrive, please store them standing up straight (so don't lay the package flat) and make sure the old ones are on top of the new ones, just like people do in supermarkets!
Both print heads and ink cartridges have best-before dates, so when you replace them be sure to pick the oldest one available. This date is marked on the back side of the card-board packaging, along with where it was made (most often, Singapore.).
It's not a problem if the print head is a couple of months past the expiry date, as long as it's not more than 8 months.
The HP Designjet Z21oo has 8 cartridges. HP 70 cartridges can be bought per one pack of 130 ml.
Left side of the printer:
- HPC9453A Magenta
- HPC9454A Yellow
Right side of the printer:
- HPC9455A Light Magenta
- HP C9390A Light Cyan
- HPC9448A Matt Black
- HPC9451A Light Grey
- HPC9449A Photo Black
- HPC9452A Cyan
You can buy them at 123inkt.nl for 63,50 euro incl. btw
password: get the password from Jans.
(or at Paper-graphics for 62,00 euro excl. btw)