Which toner fits the HP Color LaserJet M651dn?

The exact list, to be copied as it stands

The four codes differ only in their last digit, and the order of the colours is not the one you would expect:

• black — CF320A (HP 652A);
• cyan — CF331A (HP 654A);
• yellow — CF332A (HP 654A);
• magenta — CF333A (HP 654A).

Note carefully: yellow comes before magenta in HP's numbering, against the usual cyan-magenta-yellow order. An order placed "in order" therefore delivers two colours swapped — mechanically harmless, but it stops a machine for as long as the exchange takes.

Why the black has its own family

Because its yield and its formulation differ from those of the colours. HP separates the two into 652A and 654A, and there is no such thing as a "654A black". Asking a supplier for four 654A, which seems logical, means ordering three usable cartridges and one that does not exist.

A production machine: what the pace implies

The M651dn prints 42 pages per minute in colour, with a cycle that can reach 120,000 pages a month, a touchscreen and automatic duplex. At that rate, black runs out three to four times faster than each colour: keeping one spare black is enough in most cases, and ties up far less money than a full set in reserve.

The Color LaserJet CP4025dn has the same black/colour split, and its page sets out the maintenance parts — collection unit, fuser, transfer belt — that matter as much as the toners on this kind of machine.