HP 712 3-pack 29-ml Magenta DesignJet Ink Cartridge (3ED78A)

Which printers take this part

Of the machines we sell, this fits the HP DesignJet T650 in both the 24-inch and 36-inch builds. If your machine is not a T650 it takes a different part — check the number printed on the tank you are replacing, then find it in the genuine HP part list.

Why a three-pack

Three tanks in one carton means a low-ink alert does not stop a run mid-job, and one requisition covers the spares rather than three. Each is a standard 29-ml cartridge; the carton changes the ordering, not the ink or the way the printer takes it. Magenta is one of the colors that sees steady use across most color posters, and in our 712 range the three process colors are the ones sold in cartons of three.

Carton or singles

The same cartridge is sold one at a time as 3ED68A. Buying the three together costs less per milliliter than buying three singles, and the ink inside is the same, so the single is only worth ordering when you genuinely want one tank. Both prices are shown on their own pages; check them there rather than taking a figure from a description that can go stale.

Don’t order this one by mistake

The single magenta is 3ED68A; this code bills three. One character apart are the other cartons — 3ED77A is cyan and 3ED79A is yellow — and 3ED70A and 3ED71A are black singles at 38 ml and 80 ml. Quote all six characters on the PO.

Specification

Practical questions on the magenta carton

Do all three cartridges have to go in at once?

No. Load one when the printer asks for it and keep the other two boxed as spares.

Is there a three-pack of black as well?

Not in our range — black comes as single tanks, 3ED70A at 38 ml or 3ED71A at 80 ml.

Is the ink in the carton the same as in the single cartridge?

Yes. Three tanks of the same genuine HP 712 magenta, packed together so one order line covers the spares.

School POs welcome on every ink order. Not sure which part fits your machine? See all genuine HP parts by number.