HP 51X Black Toner Cartridge (Q7551X) – High-Yield Compatible | Castle Ink

HP 51X Black (Q7551X) at a glance: a high-yield black toner cartridge rated at about 13,000 pages. Compatible: newly manufactured to HP's specifications. Fits the HP LaserJet P3005 and M3027/M3035 MFP. The imaging drum is built in. Backed by a 1-year 100% satisfaction guarantee; orders by 4 PM ET (Mon–Fri) ship the same day from Long Island, NY.

Key Facts

What's in the Box

• 1 × HP 51X Black (Q7551X) compatible toner cartridge — about 13,000 pages

Page yields are the manufacturer's rating for the matching original cartridge, measured at roughly 5% page coverage under ISO/IEC 19752 or 19798 testing. Your results will vary with what you print.

Compatible Printers (9 models)

• HP LaserJet P3005
• HP LaserJet P3005d
• HP LaserJet P3005dn
• HP LaserJet P3005n
• HP LaserJet P3005x
• HP LaserJet M3027 MFP
• HP LaserJet M3027x MFP
• HP LaserJet M3035 MFP
• HP LaserJet M3035xs MFP

Don't mix these up: HP 51X is the high-yield version of 51A and fits the same slot. It is not the same as HP 55A/55X (P3015) or HP 53A (P2015).

Not sure? Look up your exact model on our Find Ink by Printer page, or contact us and we'll confirm the right toner for you.

Part Numbers & Also Known As

This toner cartridge replaces or is also searched for as: Q7551X, HP Q7551X, HP 51X black, HP51X black, 51X black toner, P3005 black toner, M3035 black toner

Chips, Printer Messages & Installation

Installing: open the printer's toner door, pull out the empty cartridge by its handle, then rock the new cartridge gently side to side five or six times to spread the toner. Remove the orange shipping lock and pull the sealing tape straight out, then slide the cartridge in until it seats and close the door.

Chip and supply messages: this compatible cartridge carries its own chip. The printer may show a "non-HP" or "used supply" notice; press OK to continue. If the cartridge isn't recognized, remove it, check that all packing material is off and reseat it firmly. Keeping automatic firmware updates off avoids most chip problems.

Streaks or faint print: rock the cartridge again to redistribute toner and print a cleaning page from the printer menu. See laser printer streaks and lines.

Still stuck? See our guide to fixing a cartridge that isn't recognized or contact us and we'll make it right.

Compatible vs. Remanufactured vs. Original

Original (OEM) toner is new from the printer brand and costs the most. Compatible toner, like this cartridge, is newly manufactured by a third party to the original's size, chip and page-yield specifications, so it drops into the same slot at a much lower price. Remanufactured toner is an emptied original cartridge that has been rebuilt and refilled. Castle Ink sells compatible (newly manufactured) toner and remanufactured inkjet cartridges.

Other Options for the Same Printers

• HP 51A Black (Q7551A)

Frequently Asked Questions

How many pages does the HP 51X Black print?

About 13,000 pages, based on HP's rating for the original Q7551X at roughly 5% coverage.

Is it a drop-in replacement?

Yes. It installs the same way as the original HP cartridge, with the drum built in, so there is nothing else to replace.

Will this void my printer warranty?

No. Under the U.S. Magnuson-Moss Warranty Act, a manufacturer can't void your printer warranty just because you used a third-party or remanufactured supply. If a non-original supply directly caused damage, that specific repair might not be covered.

How long can I store it?

Sealed toner keeps for about two years at room temperature. Keep it in its bag, away from heat and direct sunlight, and store it flat.

When will my order ship?

Orders placed by 4 PM ET, Monday through Friday, ship the same business day from Long Island, NY, by USPS (2–5 business days). Expedited 1–2 day delivery is available at checkout, and shipping is free on orders over $50.