A Fax Machine with a Toner Habit

Most printers on this site chose their pages. The FAX-2840 does not: it is a dedicated laser fax machine — 33.6K bps modem transmitting a page in about 2.5 seconds, a telephone handset on the side, the ability to share one line between fax and voice calls, even a connection for an external answering machine — and it prints whatever the phone line brings it, whenever it arrives. It also makes convenience copies, and its USB connection lets it double as a laser printer at up to 21 pages per minute.

That profile drives its supply advice. A fax machine cannot be allowed to run dry: documents it cannot print wait in its 400-page memory, and a busy line keeps adding to the pile. Add that it shipped with a starter cartridge of only about 700 pages, and the case for fitting the high-yield cartridge — and keeping the drum healthy — makes itself.

The Running Costs

Supply	Rated yield	Our compatible price*	Cost per page
TN420	~1,200 pages	$23.59	~2.0¢
TN450	~2,600 pages	$23.59	~0.9¢
DR420 drum	~12,000 pages	$26.52	~0.2¢

*Prices taken from the product pages on November 2, 2026; they can change. Yields are Brother's ratings.

Our TN420 and TN450 cost the same $23.59. For a machine whose workload arrives uninvited, over the phone line, the TN450's roughly 2,600 pages at about 0.9¢ each are the prudent standing choice — more than double the buffer before an empty machine starts parking faxes in memory.

How to Replace the Toner Cartridge

1. Leave the FAX-2840 on and open the front cover. 2. Slide the drum-and-toner assembly out and set it on a sheet of paper. 3. Press the green lock lever and lift the old cartridge out of the drum. 4. Rock the replacement cartridge gently from side to side, then remove the protective cover. 5. Click the cartridge into the drum until the lever rises on its own, slide the drum's green tab back and forth to clean the corona wire, and return the tab to its home mark. 6. Refit the assembly and close the cover; any faxes held in memory will now print.

Covering Toner and Drum Together

At around 12,000 pages, the DR420 drum that images every incoming fax reaches its own limit. Our TN450 + DR420 toner and drum set replaces both parts in one box for $34.03, saving $16.08 versus the $50.11 they cost separately. The honest qualification, as always: if the drum still has most of its life left, the $23.59 toner alone is the complete order, and the set belongs to drum day.

Why Fax Lines Deserve the Bigger Cartridge

Consider what an empty cartridge means on each kind of device. On a printer, work pauses until someone deals with it — annoying, visible, quickly fixed. On a fax machine sitting in a back room, nobody may notice for days, while the memory quietly fills with other people's documents: orders, referrals, signed forms, the paperwork of businesses that still run on fax. The machine's 400-page buffer softens that risk; the TN450 shrinks it at the source by more than doubling the pages between changeovers for exactly the same shelf price as the standard cartridge. For unattended equipment, that margin is not a luxury — it is the operating plan.

Frequently Asked Questions

My FAX-2840 is listed as "IntelliFax-2840" on cartridge boxes. Same machine? The same. Brother brands it both ways; the store category and Brother's compatibility list use both names for one device, and its supplies are TN420, TN450 and DR420 either way.

What happens to incoming faxes when the toner runs out? They are received into the machine's memory — up to about 400 pages — and printed once a fresh cartridge is fitted. It is a safety net, not a strategy; the high-yield cartridge keeps you out of it.

Why did the cartridge that came with the machine end so quickly? It was a starter cartridge rated around 700 pages. Retail TN420 and TN450 cartridges hold considerably more, so your second cartridge will outlast your first by a wide margin.

Can the FAX-2840 really work as a computer printer? Yes — its USB interface prints at up to 21 pages per minute. Those computer-printed pages draw on the same cartridge and drum as faxes and copies.

How do I know whether a fault is the toner or the drum? Fading that a fresh cartridge fixes was toner. Repeating marks or a gray cast that survive a cartridge change implicate the DR420 — clean the corona wire with the green tab before replacing it.

Other Printers That Use TN420, TN450 and DR420

Your fax machine shares its cartridge and drum with fifteen printers and all-in-ones:

• HL-2220
• HL-2230
• HL-2240
• HL-2240D
• HL-2270DW
• HL-2275DW
• HL-2280DW
• DCP-7060D
• DCP-7065DN
• MFC-7240
• MFC-7360N
• MFC-7365DN
• MFC-7460DN
• MFC-7860DW
• FAX-2940

Ready to order? Start from our FAX-2840 toner page, which lists every cartridge, drum and set that fits this machine.