Step up from the DCP-8110DN to the DCP-8150DN and the changes are about paper, not printing: a legal-size document glass replaces the letter-size one, the automatic document feeder grows from 35 to 50 sheets, and the engine quickens slightly to 40 pages per minute. Underneath, the supply shelf is identical — which is precisely the point of this guide. Everything you may have learned about another family member's toner applies here, with the volumes nudged upward.

Legal-Size Glass, Legal-Size Appetite

The legal-size glass is this model's signature. Law offices, real-estate desks and clinics copy bound legal documents, ledger pages and charts that will not fit a letter-size platen, and those copies are printed pages — toner pages. A 40 ppm copier with a 50-sheet feeder turns a stack of files into a stack of copies before lunch. Brother rates the family cartridges at about 3,000 pages for the TN720 and about 8,000 for the TN750; on a machine whose specialty is document throughput, the smaller rating evaporates quickly.

The Cost Table

Supply	Rated yield	Our compatible price*	Cost per page
TN720	~3,000 pages	$29.21	~1.0¢
TN750	~8,000 pages	$29.21	~0.4¢
DR720 drum	~30,000 pages	$36.33	~0.1¢

*Prices isolated from the product pages on November 2, 2026; they can change.

Both cartridges sit at $29.21 here, so the choice is no choice at all: the TN750 cuts toner cost per page from about a cent to about four-tenths of a cent and nearly triples the interval between swaps, for zero additional dollars. The drum works out to roughly a tenth of a cent per page over its 30,000-page life, which is why drum planning is about timing rather than price.

Replacing the Cartridge

1. Leave the machine powered, open the front cover, and pull the drum-and-toner assembly out toward you. 2. Rest it on scrap paper, press the green lock lever down, and lift the spent cartridge out of the drum cradle. 3. Give the new cartridge a slow side-to-side rock, remove the protective cover, and seat it in the drum until the lever snaps up on its own. 4. Run the drum's green corona-wire tab from one end to the other and back, finishing with the tab at its arrow mark. 5. Slide the unit home, close the cover, and let the copier cycle back to Ready.

One Box for the Day Both Parts Come Due

A DR720 drum spans roughly four TN750 cartridges, so its replacement usually lands on its own schedule. When the drum's turn and a toner order coincide, our TN750 + DR720 set covers the pair for $49.46 — $16.08 less than the $65.54 separate total. The balanced view matters as much as the saving: a mid-life drum under a fresh TN750 is a complete setup, and buying the set early only parks a drum in a cupboard.

Frequently Asked Questions

Does copying from the legal glass use more toner than printing? Page for page, no — a copy is a print with a scanned original. What the legal glass changes is volume and coverage: legal documents often carry dense text and stamps, and dense coverage is what shortens real-world yield against the 5%-coverage rating.

Can the DCP-8150DN scan both sides automatically? No — its feeder and glass scan one side at a time. If two-sided originals are a daily burden, the DCP-8155DN adds single-pass duplex scanning while using exactly the same TN720, TN750 and DR720 supplies.

Why does my feeder copy run look lighter than glass copies? The feeder's scan strip accumulates dust and correction-fluid specks that the glass path avoids. A soft, dry cloth along the narrow glass strip beside the main platen usually cures it — it is a scanner cleaning issue, not a toner shortage.

Is the TN780's extra capacity available to me some other way? Not in a single cartridge; 8,000 pages is this model's ceiling. Owners who want fewer interventions keep a second TN750 on the shelf — at $29.21, the spare costs less than the downtime it prevents.

What warranty came with this machine, and does toner choice affect it? Brother sold the DCP-8150DN with a 3-year limited warranty (2-year exchange, 1-year depot). That term has run its course for most units by now; your compatible cartridge choice today is a running-cost decision, not a warranty one.

Other Printers That Use TN720, TN750 and DR720

Everything in this guide applies to the rest of the generation as well:

• HL-5440D
• HL-5450DN
• HL-5470DW
• HL-5470DWT
• HL-6180DW
• HL-6180DWT
• DCP-8110DN
• DCP-8155DN
• MFC-8510DN
• MFC-8710DW
• MFC-8810DW
• MFC-8910DW
• MFC-8950DW
• MFC-8950DWT

Ready to restock? Start from our DCP-8150DN toner page, which lists every cartridge, drum and set that fits this printer.