What Ink Does the Epson WF-7840 Use?

Quick answer: The Epson WorkForce Pro WF-7840 uses four individual Epson 812 DURABrite Ultra pigment cartridges: Black, Cyan, Magenta and Yellow. The high-capacity Epson 812XL cartridges fit the same slots and print about 1,100 pages each. That's more than three times a standard black, so they're the one to buy for a wide-format office printer.

Epson WF-7840 Ink Cartridges at a Glance

Epson 812 fits four printers: the WorkForce Pro WF-7840 and WF-7820 all-in-ones, the WF-7310 printer and the WorkForce EC-C7000. It does not fit the smaller WorkForce Pro WF-3820 and WF-4820, which take Epson 822. It also won't fit the older WF-7710/7720, which use Epson 252. The ink is pigment-based in all four colors, so prints hold up well against water and highlighters. That's one reason the WF-7840 is popular for plans, spreadsheets and 11 x 17 handouts. Here's more on pigment vs. dye ink.

Save on Epson 812 / 812XL

Castle Ink doesn't stock Epson 812 cartridges right now, so we won't pretend otherwise. The best value is the XL size. Epson also sells a combo with an XL black and standard colors (T812XL-BCS), which suits offices that mostly print text. You can compare genuine and remanufactured 812XL options here: Epson 812XL ink on Amazon (as an Amazon Associate we earn from qualifying purchases).

Tabloid and 13 x 19 prints with heavy color coverage use ink quickly, so it's worth checking your real cost per page with our printer ink cost calculator. If you run other Epson, HP, Canon or Brother printers too, we very likely stock their ink. Look them up on the Find Ink by Printer page.

How to Replace Ink in the Epson WF-7840

1. Turn the printer on. When the screen shows an ink warning, choose the option to replace cartridges (or go to Maintenance > Ink Cartridge Replacement).
2. Lift the scanner unit. The cartridge holder moves to the replacement position. Don't move it by hand.
3. Squeeze the tab on the empty cartridge and lift it straight out.
4. Gently shake the new cartridge four or five times, unwrap it and remove the yellow tape. Don't touch the green chip.
5. Insert it into the slot for its color and press down until it clicks.
6. Close the scanner unit. The printer charges the ink, which takes a minute or two, then it's ready.

Troubleshooting Tips

"Cannot recognize the ink cartridge": Remove it, check that all the yellow tape is off, and press it down firmly until it clicks. After an Epson firmware update, some third-party chips stop working, so buy compatibles from a seller who guarantees current chips. More fixes in printer says ink cartridge not recognized.

Banding or missing lines on wide prints: Run a Nozzle Check from Maintenance, then Print Head Cleaning if you see gaps. The WF-7840's PrecisionCore printhead is permanent, so stop after two or three cleanings, let the printer rest a few hours, and try again. See faded or streaky prints for more.

Printer stops with a maintenance box message: The WF-7840 has a replaceable maintenance box that collects ink from cleaning cycles. When it's full, the printer stops until you replace it. That's normal and separate from the ink cartridges.

Official Epson Resources

• Epson Support
• Epson WF-7840 ink and supplies

Bottom Line

The Epson WorkForce Pro WF-7840 takes Epson 812 or 812XL in four pigment colors. Buy XL, especially if you print tabloid or 13 x 19, and don't confuse it with the Epson 822 used by the smaller WF-3820 and WF-4820.

Written and reviewed by William Elward — Founder of Castle Ink, 20+ years in the printer & imaging supplies industry.

Frequently Asked Questions

Does the WF-7840 use the same ink as the WF-7820?
Yes. Both take Epson 812 and 812XL. The WF-7820 simply lacks some of the 7840's paper-handling extras.

Will Epson 822 or 252 cartridges fit the WF-7840?
No. Epson 822 is for the WF-3820/4820/4830 and Epson 252 is for the older WF-7710/7720/7620. Neither fits the WF-7840.

Can I print black only when a color runs out?
Epson printers usually need all four cartridges to have ink. Some models allow short-term black-only printing from the computer, but plan on replacing the empty color.

Does using compatible ink void my Epson warranty?
No. Under the U.S. Magnuson-Moss Warranty Act, Epson can't void your printer warranty just because you used third-party cartridges.

Shop Compatible Ink at Castle Ink

Find the right cartridge for the Epson WF-7840 and every other printer we cover on the Find Ink by Printer page, or work through a fault at our printer troubleshooting center.

Buy the Epson WorkForce Pro WF-7840 on Amazon: Epson WF-7840 on Amazon — as an Amazon Associate we earn from qualifying purchases.

See also: what ink the Epson WF-3820 uses | printer printing the wrong colors | paper sizes explained