Make sure you purchase the right ink cartridges for your specific printer and printer region or have your old ones refilled. Cartridges are not compatible between different brands, and often not within the same brand. HP often designs its inkjet hardware to use country-specific consumables. When you unbox a new HP inkjet printer and set it up, you install a set of ink tanks that ship with the printer. As you turn on the device and get ready to use it, an initialization sequence localizes it to the country associated with the ink cartridges you installed.
HP recommends that you use Original HP ink cartridges. XL (Extra Large) cartridges cost more but do provide better value in the long run. They will be able to print at least double the pages of a regular cartridge. Our advice is that if you print often, go with XL. However, ink can dry up. So if you are not a frequent printer, go with the regular cartridges.
You can check the estimated ink levels from the printer software or from the printer control panel. The icon below displays a screen where you can see information about the ink cartridges, including fill levels. This icon has a red border when an ink cartridge needs attention. Ink level alerts and indicators provide estimates for planning purposes only. When you receive a low-ink alert, consider having a replacement cartridge available to avoid possible printing delays. You do not have to replace the cartridges until you are prompted to do so.
For regular usage, this product is not designed to print using only the black cartridge when the color cartridges are out of ink. However, your printer is designed to let you print as long as possible when your cartridges start to run out of ink. When there is sufficient ink in the printhead, the printer will offer you the use of black ink only when one or more of the color cartridges are out of ink, and the use of color ink only when the black cartridge is out of ink. The amount that you can print using black or color ink only is limited, so have replacement ink cartridges available when you are printing with black or color ink only. When there is no longer sufficient ink to print, you will get a message that one or more cartridges are depleted, and you will need to replace the depleted cartridges before you resume printing.
For your US, European and UK HP Officejet Pro 251dw Printer you need an HP 950 Black cartridge and 3 color cartridges: HP 951 Cyan/Magenta/Yellow. There are also Combo Savers (4 cartridges in one pack) available, like the HP 950XL Black and 951 Tri-color (Cyan, Magenta, Yellow) Combo Saver.
Insert a new cartridge
4. Remove the new ink cartridge from its packaging. Do NOT touch the electrical contacts and ink port.
Do NOT lift the latch handle on the print carriage to install the ink cartridges. Doing so could cause the printhead or ink cartridges to be incorrectly seated, which can cause errors or print quality problems. The latch must remain down in order to correctly install the ink cartridges.
5. Using the color-coded letters for help, slide the ink cartridge into the empty slot until it snaps into place and is securely installed in the slot. Make sure that you insert the ink cartridge into the slot that has the same colored letter as the color you are installing.
6. Repeat steps 3 through 5 for each ink cartridge you are replacing.
Align the printhead only if necessary.
The printer automatically aligns the printhead during the initial setup. You might want to use this feature when the printer status page shows streaking or white lines through any of the blocks of color or if you are having print quality issues with your printouts. You can align the printhead from the printer’s control panel, from the Toolbox (Windows) or HP Utility (OS X), and from the embedded web server (EWS).