What Ink Does the HP DeskJet 3940 Use?

by Lauren Elward Last Updated: October 17, 2026

Quick answer: The HP DeskJet 3940 uses two cartridges: an HP 21 black and an HP 22 tri-color. Castle Ink stocks remanufactured HP 21 Black, HP 22 Tri-color and a 21 + 22 combo pack.

It takes the same ink as the DeskJet 3910, 3915 and 3930, the DeskJet F4180 and F380 all-in-ones, and many D-series DeskJets. The 3940v variant takes the same cartridges. European 3940s also use HP 21 and 22, with an AE suffix on the part number. The high-yield 21XL and 22XL were sold in Europe and Asia, but we couldn't confirm a U.S. version.

CastleScore · October 2026

63/100 — Situational

HP DeskJet 3940

Pillar (weight)	Score	What it is based on
Owner ratings (28%)	—	No retailer rating with enough reviews to use.
Expert reviews (18%)	58	Average of three German-language magazine tests of the European model via testberichte.de: PCgo 76/100 (2005), Konsument 49% and com! professional 48/100 (2006)
Cost per page (24%)	74	About 7.5¢ per page blended (black + color) with our remanufactured HP 21 black (190 pages) and HP 22 tri-color (165 pages).
Reliability (13%)	80	Most-reported problems: no driver on newer Windows without the original disc; cartridge light blinking after a swap; slow printing in normal mode; high running cost from small cartridges
Features (12%)	28	Print only, over USB. No scanner, no display, no Wi-Fi or Ethernet, no document feeder, no auto two-sided printing, no fax.
Value (5%)	70	Running cost and owner satisfaction

Limited data: We could not find enough owner ratings for this printer, so that weight is spread across the other pillars.

Discontinued. HP released the DeskJet 3940 around 2005, and Icecat records an HP end-of-life date of August 2011. HP 21 and 22 cartridges are still sold.

CastleScore is Castle Ink’s own editorial rating, built from retailer star ratings, expert reviews, real cost per page and owner complaint patterns, checked October 17, 2026. It is not a customer review. See every ranked printer or how the score works.

The cartridges, pictured

Our own remanufactured cartridges, photographed in-house.

What Ink Cartridges Does the HP DeskJet 3940 Take?

Cartridge	HP part no.	Approx. yield	Castle Ink option
HP 21 Black	C9351AN	~190 pages	Remanufactured HP 21 Black
HP 22 Tri-color	C9352AN	~165 pages	Remanufactured HP 22 Tri-color
HP 21 + 22 combo pack	C9509FN	~190 / 165 pages	Remanufactured 21 + 22 combo
HP 21XL Black	See note	~475 pages	—
HP 22XL Tri-color	See note	~415 pages	—

The XL cartridges are sold as C9351CE and C9352CE in Europe and C9351C and C9352C in Asia-Pacific. We couldn't confirm U.S. part numbers, and 4inkjets lists only the standard 21 and 22 for the 3940. HP's 21 black twin pack (C9508FN) is listed as discontinued.

Is HP 21XL Worth It?

It would be, but U.S. owners can't easily get it. That leaves the standard cartridges. On October 17, 2026, Staples listed HP's 21 black at $31.89 (about 16.8¢ a page) and the 22 tri-color at $48.99 (about 29.7¢ a page), out of stock for delivery. 4inkjets listed HP's 21 + 22 combo at $55.99, backordered. Our remanufactured HP 21 black is $11.99 (about 6.3¢ a page) and the HP 22 tri-color $16.99 (about 10.3¢ a page), or $26.99 for the combo pack.

How Do I Replace the Ink in the HP DeskJet 3940?

Turn the printer on and open the front cover. Wait for the cartridge carriage to move to the center and stop.
Push down on the old cartridge and pull it out of its stall. Tri-color goes on the left, black on the right.
Unwrap the new cartridge and pull off the pink tape by its tab. Don't touch the copper contacts or nozzles.
Slide the cartridge into its stall at a slight upward angle, contacts toward the printer, and push until it snaps in.
Close the cover and print the alignment page when asked, or run Align from the printer software.

Which Other Printers Use HP 21 and 22?

The DeskJet 3910, 3915 and 3930; the DeskJet D1311, D1320, D1330, D1341, D1360, D1420, D1430, D1445, D1455, D1520, D1530 and D1560; the DeskJet D2320, D2330, D2345, D2360, D2430, D2445 and D2460; the DeskJet F335, F340, F350, F380, F2110, F2140, F2180, F2210, F2240, F4135, F4140 and F4180; the OfficeJet J3640, J3680 and 4315; the PSC 1410; and the HP Fax 1250.

What DeskJet 3940 owners ask

These are the questions that come up most for this printer in HP's support community and owner reviews, answered in our words.

How do I install it without the original CD?

HP no longer offers a full software package. Add a local printer on the USB port in Windows, run Windows Update, and pick HP Deskjet 3920/3940 from the built-in driver list. HP staff gave this method on HP's forum, and an owner confirmed it works on Windows 10.

The cartridge light is blinking after I changed a cartridge.

The cartridge is usually unseated, still has its tape on, or has dirty contacts. Pull off the pink tape, wipe the copper contacts with a lint-free cloth and reseat it. If the light keeps blinking, replace the cartridge.

Can it scan, copy or print over Wi-Fi?

No. It's a print-only printer that connects by USB. There's no scanner and no wireless or network port.

Is there a high-yield cartridge?

HP's 21XL and 22XL (about 475 and 415 pages) were sold in Europe and Asia. We couldn't confirm a U.S. XL part, so U.S. owners buy the standard 21 and 22.

DeskJet 3940 quirks worth knowing

HP rated it at up to 16 pages a minute in black and 12 in color, in draft mode. ITC.ua measured about 6.5 pages a minute for black text and about 2 for color in normal mode.
The 80-sheet input tray doubles as the output tray: printed pages stack on top of the paper.
Sources disagree on whether it prints borderless. HP rated it for up to 500 pages a month.
German testers scored it low partly for running costs. The standard cartridges print only about 190 and 165 pages.

Frequently Asked Questions