Our take
Lexmark's T640 is a monochrome workgroup printer for a buyer who wants documented volume guidance rather than a speed claim alone. The U.S. product page maps part 20G0100 to a T640 rated up to 35 pages per minute and recommends 3,000 to 14,000 pages per month. It also lists 350 sheets of standard input and USB and parallel ports. Automatic duplex is available as an option, not a base feature, so a listing must include the duplex unit to match that need. Lexmark's page gives conflicting Ethernet information, which leaves that attribute unresolved. It is a substantial used-office choice that requires configuration checks.
A wired workgroup considering a used high-volume monochrome printer that can verify its exact interfaces and optional duplex hardware before purchase..
Avoid it if you need built-in wireless, guaranteed Ethernet, automatic duplex in the base unit, color output or a compact personal printer.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- Lexmark documents a 3,000–14,000 page monthly recommendation and a 35 ppm rating.
- Standard paper input is 350 sheets, with USB and parallel interfaces listed.
- Optional duplex lets an equipped unit support automatic two-sided print jobs.
What to weigh up
- Automatic duplex is optional and should not be assumed from the T640 name alone.
- The reviewed Lexmark page conflicts on Ethernet, so that connection is left unknown.
- The T640 is a monochrome printer without copy, scan or fax functions.
The key details
| Model covered | T640 (20G0100) |
|---|---|
| Main functions | Monochrome print-only; rated up to 35 ppm |
| Print output | 3,000–14,000 recommended pages per month; 350-sheet input |
| Two-sided printing | USB and parallel standard; duplex optional; Ethernet status unresolved |
Performance figures are manufacturer claims. Source checked October 7, 2026. Regional models and included accessories can differ.
What the features mean for you
Match the workload to Lexmark's stated recommendation
The T640's clearest buying signal is its recommended monthly range: Lexmark lists 3,000 to 14,000 pages. This gives an office a more grounded comparison than a maximum duty-cycle number, although a printer's real life still depends on maintenance, consumables and job mix. The 35 pages-per-minute rating suggests that the machine was designed around recurring business documents rather than occasional household output. A small desk with very light use may find the footprint and setup effort disproportionate, while an office with regular black-only batches can use the recommendation as one part of a shortlist. Do not extend the stated range beyond what Lexmark actually publishes.
Confirm whether the optional duplexer is installed
Lexmark identifies duplex capability as an option for the T640. That means an advertised base model does not automatically satisfy a request for automatic two-sided printing. Ask for a photo of the rear path or installed duplex unit, and inspect its operation before relying on it. The optional hardware changes how the printer can handle multi-page documents and may affect the machine's configuration, so a generic listing title is not enough evidence. The catalog marks automatic duplex false for the standard base setup and explains the option in the review. If duplex is essential, only consider a seller who can show that the matching component is present and functioning.
Paper capacity supports an office queue
The product page lists 350 sheets of standard input. That supply is useful when a shared printer handles repeated forms or packets, since the cassette can hold more than a small desktop tray. It is not a substitute for checking the exact paper path, media sizes or optional expansions, and it does not establish a print-volume recommendation on its own. The stated monthly guidance is a separate decision input. Before placing a used T640 into a common area, check whether the tray guides, output area and feed rollers work with the paper sizes staff use. A high capacity printer still needs the right placement and an agreed replenishment routine.
Plan connections conservatively
Lexmark lists USB 2.0, USB direct host and IEEE 1284 parallel as standard ports for this part. Its U.S. product page also contains inconsistent Ethernet information between the descriptive text and standard-port table, so the catalog leaves Ethernet unresolved instead of promising wired network access. Built-in wireless is not listed. For an office that needs network printing, inspect the rear ports on the actual unit or obtain written confirmation of the installed network option before buying. A USB connection can serve a direct workstation, but a team should not plan a shared queue around a port that remains uncertain.
Inspect an older enterprise printer before making it dependable
Part 20G0100 helps identify the T640 base configuration, but it does not say whether a specific used machine includes add-ons or has been maintained. Check the model plate, trays, duplex option, network accessories, toner system and page-feed behavior. Confirm driver support for the operating systems in the planned environment, and ask about service history and return terms. The machine's rated speed and workload recommendation describe its intended capabilities; they do not certify the condition of an individual offer. Lexmark marks this product as discontinued, so buyers should also verify that replacement supplies and service arrangements meet their own requirements.
What else to compare
Choose a printer with integrated duplex if optional hardware is undesirable, or a model with clear Ethernet and Wi-Fi specifications if shared wireless networking is mandatory.
Before you buy
What monthly volume does Lexmark recommend?
Lexmark lists a recommended monthly range of 3,000 to 14,000 pages for the T640.
Does the base T640 have automatic duplex?
Lexmark lists duplex as optional, so verify that a duplex unit is installed on the exact machine.
Can I rely on Ethernet networking?
The reviewed Lexmark page conflicts on Ethernet details; inspect the exact unit or confirm its port configuration.
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.
- Lexmark U.S. T640 product page ↗ — checked October 7, 2026.
- Lexmark U.S. T640 part 20G0100, speed, recommended volume, paper and interface information ↗ — checked October 7, 2026.
The decision
The T640 offers a useful published workload range and office-scale paper input, but its duplex and Ethernet configuration must be checked on the exact unit.
Is it the right fit?
Check the exact model and today’s offers on Amazon.