Product Specifications
| SKU | R-42377801 |
|---|---|
| OEM Part Number | 42377801 |
| Cartridge Type | Printer Ribbon |
| Compatible Brand | OKI |
| Color | Black |
| Condition | New compatible (non-OEM) |
| Warranty | 100% Satisfaction Guarantee |
Product Description
Okidata ML-420/421/490/491/720/790 Black (42377801) at a glance: a dot-matrix printer ribbon cartridge in black, rated at about 4 million characters. Compatible: newly manufactured to fit and print like the original. Sold as a 6-pack. Fits the Okidata Microline 420, Okidata Microline 420n, Okidata Microline 421 and 9 more. Backed by a 1-year 100% satisfaction guarantee; orders by 4 PM ET (Mon–Fri) ship the same day from Long Island, NY.
Key Facts
| Condition | Compatible (newly manufactured) |
| Replaces OEM part | 42377801 (Okidata — 42377801B, 42377801PC, Innovera IVR42377801) |
| Color | Black |
| Pack size | 6 ribbons |
| Yield | About 4 million characters per ribbon |
| Ribbon type | Nylon fabric ribbon |
| Guarantee | 1-year 100% satisfaction guarantee: replacement or refund |
| Shipping | Same business day when ordered by 4 PM ET (Mon–Fri); free shipping on orders over $50 |
What's in the Box
- 6 × compatible Okidata ML-420/421/490/491/720/790 black ribbons (42377801) — about 4 million characters each
Compatible Printers (12 models)
- Okidata Microline 420
- Okidata Microline 420n
- Okidata Microline 421
- Okidata Microline 421n
- Okidata Microline 490
- Okidata Microline 490n
- Okidata Microline 491
- Okidata Microline 491n
- Okidata Microline 720
- Okidata Microline 721
- Okidata Microline 790
- Okidata Microline 791
Don't mix these up: Current-generation OKI 9-pin ribbon for the ML-420/421 (narrow) and ML-490/491 (wide), plus the 720/721/790/791. The older ML-320/390 take 52102001/52104001, a different cartridge.
Not sure? Look up your exact model on our Find Ink by Printer page, or contact us and we'll confirm the right ribbon for you.
Part Numbers & Also Known As
This item replaces or is also searched for as: 42377801B, 42377801PC, Innovera IVR42377801, 42377801, R-42377801
Installation & Troubleshooting
Installing: turn the printer off, open the cover and lift out the old cartridge. Turn the knob on the new cartridge to take up any slack, slide the ribbon between the print head and the ribbon guide, press the cartridge down until it clicks, then turn the knob once more. Print a test receipt to confirm the ribbon is seated.
Faint or patchy print: make sure the ribbon is seated in front of the print head and the take-up knob has been turned to remove slack. If print stays faint after a fresh ribbon, the print head may need cleaning.
Compatible (Newly Manufactured) vs. Original
Original (OEM) supplies are new from the printer brand and cost the most. Compatible supplies, like this one, are newly manufactured by a third party to fit and print like the original at a lower price. Castle Ink sells remanufactured inkjet cartridges and compatible (newly manufactured) toner, drums, ribbons and fax film.
Frequently Asked Questions
Which printers use the Okidata ML-420/421/490/491/720/790 ribbon?
Okidata Microline 420, Okidata Microline 420n, Okidata Microline 421, Okidata Microline 421n, Okidata Microline 490, Okidata Microline 490n, Okidata Microline 491, Okidata Microline 491n and 4 more (full list above).
How long does one ribbon last?
The original is rated at about 4 million characters. Fabric ribbons fade gradually rather than running out, so replace it when receipts or printouts become hard to read.
Is black the right color?
Black is the standard color for most printers and receipt stations.
Will a compatible ribbon damage my printer?
No. The cartridge is built to the original dimensions and uses the same nylon fabric and ink type, so it installs and prints like the original.
When will my order ship?
Orders placed by 4 PM ET, Monday through Friday, ship the same business day from Long Island, NY, by USPS (2–5 business days). Expedited 1–2 day delivery is available at checkout, and shipping is free on orders over $50.
- See all POS & Printer Ribbons