Our take
The Brother MFC-9840CDW is a color laser multifunction center for a desk or small office that needs more than output alone. Brother's exact-model material identifies print, copy, scan and fax, automatic print duplex, wireless networking and Ethernet. The specifications list up to 21 pages per minute on Letter paper, a 50-sheet document feeder, a 250-sheet main tray and a 50-sheet multipurpose feed. That combination supports shared paperwork without relying on a separate printer and copier. The sources do not state a recommended monthly range, and they do not establish that the ADF scans both sides automatically.
A small office that needs color print/copy/scan/fax and wants both wired Ethernet and built-in wireless in one machine..
Choose another device if you need a documented monthly workload band, a confirmed one-pass duplex document feeder, current-model support, or a compact lightweight machine.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- Brother documents color print, copy, scan and fax functions for the exact MFC-9840CDW model.
- Automatic print duplex reduces manual page handling for ordinary two-sided jobs.
- The manufacturer lists both 10/100 Ethernet and 802.11b/g wireless alongside Hi-Speed USB 2.0.
What to weigh up
- The reviewed exact-model sources do not give a recommended monthly range, so numeric workload matching is unavailable.
- The 50-sheet ADF is documented, but duplex scanning is not established; do not confuse print duplex with two-sided document capture.
- The older model's individual condition, supplies and continued software compatibility need separate checking.
The key details
| Model covered | MFC-9840CDW |
|---|---|
| Main functions | Color print, copy, scan and fax |
| Print output | Up to 21 ppm Letter; automatic two-sided printing |
| Two-sided printing | 50-sheet ADF; 250-sheet tray plus 50-sheet multipurpose feed; USB, Ethernet and Wi-Fi |
Performance figures are manufacturer claims. Source checked October 8, 2026. Regional models and included accessories can differ.
What the features mean for you
One center covers color and office document tasks
Brother calls the MFC-9840CDW a color laser multifunction center, and its specification lists printing, copying, scanning and fax. That mix can be useful where color forms, incoming paper and outgoing fax jobs share a counter or desk. The 21 ppm Letter rating gives a model-level reference for ordinary one-sided print speed, not a guarantee for every file or color mix. Because it can perform several jobs, it occupies more space and has more paths to inspect than a simple print-only machine. Buyers who never copy, scan or fax may prefer a simpler printer instead.
Automatic print duplex is not duplex scanning
Brother identifies duplex printing for this exact model, so the printer can produce the second side without requiring the user to turn the stack. This can reduce paper handling for reports or multi-page packets. A 50-sheet automatic document feeder supports scanning or copying stacks, but the saved specification does not label that feeder as duplex. Therefore, two-sided originals should not be assumed to pass through both sides in one run. Separate input and output capabilities matter: this model is established for two-sided printed output, while automatic double-sided document capture remains unconfirmed.
Choose among USB, Ethernet and wireless
Brother lists Hi-Speed USB 2.0, 10/100BaseTX Ethernet and 802.11b/g wireless. That offers a local USB route, a wired shared queue and wireless placement options. For a larger or security-sensitive office, the exact supported wireless standards may not meet newer network policy; check the router's compatibility and encryption requirements before relying on the radio. Ethernet remains a useful alternative if Wi-Fi cannot be used. Confirm the exact model suffix on a listing because adjacent Brother MFC models may have different interfaces and scanning features.
Paper handling suits routine office batches
The standard 250-sheet tray handles the main supply, while a 50-sheet multipurpose feed can keep a second paper type available. Brother lists a 50-sheet ADF for stacked originals, which is more convenient than placing every page on a glass one at a time. Optional expansion is described in the regional specification, but the exact tray configuration on any unit must be checked. There is no comparable recommended monthly range in the sources reviewed for this guide. Treat that as unknown rather than substituting a maximum duty cycle or inferring workload from the tray size.
Inspect the age and exact configuration
The MFC-9840CDW is an older model, and current condition is not established by Brother's specifications. Before choosing an individual offer, verify the model plate, fax operation, scanner glass, ADF rollers, duplex path, ports and wireless setup. Ask about toner, drums, belt and waste-toner components and confirm that the included supplies are the right fit for this exact model. Brother's model page and guide show what the original design supports; they cannot establish that a used machine still performs as designed. If software compatibility or service access is central, compare a current MFP with a similar workflow.
What else to compare
Compare a current color fax MFP if software support and service options matter, or a print-only color duplex machine if the scan, copy and fax functions would go unused.
Before you buy
Does the MFC-9840CDW print automatically on both sides?
Yes. Brother identifies duplex printing for this exact model in its official support and specification material.
Does its ADF scan both sides in one pass?
The reviewed model specifications establish a 50-sheet ADF but do not establish duplex scanning, so that detail remains unknown.
Can it use both Ethernet and Wi-Fi?
Yes. Brother lists 10/100 Ethernet and 802.11b/g wireless, in addition to Hi-Speed USB 2.0, for this model.
Where can I check the current price?
Use the Amazon link for current offers. Check the exact model, seller, product condition, delivery, and return terms. This page does not display a live price or confirm stock.
Sources & review basis
We use the following manufacturer documentation for the product features above. Our suitability notes and buying advice are editorial judgments based on those features, not measured performance results.
- Brother U.S. MFC-9840CDW support and product identity ↗ — checked October 8, 2026.
- Brother U.S. model identity and feature title for the exact MFC-9840CDW ↗ — checked October 8, 2026.
- Brother U.S. exact-model specifications for functions, speed, interfaces, trays and ADF ↗ — checked October 8, 2026.
- Brother exact-model user guide describing automatic duplex printing ↗ — checked October 8, 2026.
The decision
The MFC-9840CDW fits an office that will use its color, fax and shared-network functions and can verify the condition of an older machine. Its unknown monthly recommendation and unconfirmed duplex ADF are meaningful limits.
Is it the right fit?
Check the exact model and today’s offers on Amazon.