Okidata Microline 420/421/490/491 Compatible Black Ribbon 42377801 (6 Pack)

Compatible Black Printer Ribbons for Okidata Microline 420, 421, 490, and 491 (6 Pack)

Your Microline has probably outlasted three generations of office printers, and it is not done yet. What takes these workhorses out of service is rarely the hardware. It is bad consumables: ribbons that print faint, ribbons that almost fit, ribbons from sellers who stopped caring about dot matrix years ago. This box is the fix. Six compatible black nylon cartridges built to the exact 42377801 form factor, a perfect fit for the ML 420, 421, 490, and 491, rated at approximately 4 million characters each, and every cartridge backed by our 90-day defect guarantee. Load one, take up the slack, and your invoices and multi-part forms come out sharp again. One box covers a mixed fleet and keeps a busy counter printing for months.

Key Features

• ✅ Fits all four Microline 400-series printers (420, 421, 490, 491) with one cartridge design
• ✅ ~4 million characters per cartridge for fewer ribbon changes
• ✅ 6 cartridges per box: months of invoices, pick tickets, and multi-part forms
• ✅ Built to meet OEM specifications for fit and performance, using premium raw materials
• ✅ Every cartridge in the box is covered by our 90-day defect guarantee, not just the first one you open
• ✅ Not sure this is your ribbon? Call us before you order and we will verify the part number against your printer

Specifications

▶ Check Your Printer Model Before Ordering

Okidata used two different ribbon families across the Microline line, and ordering the wrong one is the most common mistake with this part. This cartridge fits the 420, 421, 490, and 491 only. It does not fit the Microline 182, 184, 192, 320, or 390 series. Those printers take the Okidata 52102001, which is a physically different cartridge. Each ribbon ships in clear packaging, so you can compare the cartridge shape against your old one before opening a single unit. If you are not certain which family your printer belongs to, call us first. We would rather check a part number with you than ship a ribbon that does not fit.

▶ Why Buy This Ribbon From Us

Much of the dot matrix ribbon stock sold online today comes from sellers who treat these printers as an afterthought. We treat them as a product line. TerminalDepot stocks consumables for hardware other suppliers gave up on, and our ribbons come through a national U.S. imaging-supply distributor that has been in the business since 1989, holds inventory in four U.S. warehouses (California, Texas, New York, and Illinois), builds to OEM specifications with premium raw materials, and runs an average defect rate under 1% across all cartridges. If you ever do get a bad one, the guarantee below makes it right without an argument.

▶ Our Guarantee

• Defective cartridge? If any cartridge in the box prints faint or dry on first install, or will not advance, we replace it or refund it within 90 days of purchase. That covers every cartridge in the box, even the last one you open, and opening it never voids the claim. Just send us a photo of the print output. Covers manufacturing defects, not ink used up by normal printing.
• Ordered the wrong ribbon? Check the visible cartridge through the clear packaging before opening. Unopened ribbons come back within 30 days with no restocking fee. Not sure before you order? Call us and we will verify the part number against your printer.

▶ How to Install

Power the printer off and open the access cover. Slide the print head to the center of the platen and lift out the old cartridge. On the new cartridge, turn the feed knob to take up ribbon slack, then seat it between the print head and the platen until it snaps in place. Turn the knob once more to remove any remaining slack, close the cover, and run a self-test page. If the first prints look light on single sheets, move the head-gap lever one notch closer to the platen. It is usually set for multi-part forms.

▶ Storage

Keep spare cartridges sealed in their packaging until use. Nylon ribbon ink dries with air exposure, so an opened, unused cartridge loses print density over months. Store in a cool, dry place away from direct sunlight.