HP 81 (C4930A) Black Ink Cartridge – Compatible | Castle Ink

SKU: C4930A (HP 81) | Type: Compatible Wide-Format Ink Cartridge | Color: Black | Brand: HP Compatible | Volume: 680 mL | Availability: In Stock HP 81 Black Dye Ink Cartridge (C4930A) — Compatible Replacement The HP 81 (C4930A) is a 680 mL black dye ink cartridge for the HP DesignJet 5000 and 5500 series wide-format printers. Castle Ink's compatible C4930A delivers the same deep, neutral black output and reliable nozzle performance as the genuine HP 81 cartridge — at a meaningful discount versus dwindling OEM stock. Each cartridge is precision-filled with dye-based black ink formulated for clean line work, dense fills, and smooth tonal gradients on long CAD and graphics plot runs. Why Choose This Compatible Cartridge Save up to 60% versus the genuine HP 81 (C4930A) black cartridge. True 680 mL volume for fewer cartridge changes on long DesignJet plot runs. Deep neutral black output tuned for crisp CAD line work and dense graphics fills. Drop-in installation — no firmware updates, chip swaps, or printer reconfiguration required. One-year quality guarantee from Castle Ink, with U.S.-based plotter support. Compatible Printers HP DesignJet 5000 HP DesignJet 5000ps HP DesignJet 5500 HP DesignJet 5500ps Best Use Cases This HP 81 Black is the right pick for CAD, GIS, architecture, and reprographics shops that still rely on a DesignJet 5000/5500-class plotter for production black-line drawings, technical illustrations, and large-format graphics. With genuine HP 81 inventory increasingly limited and expensive, the Castle Ink compatible cartridge keeps these heavy-duty plotters productive without forcing a capital upgrade. Frequently Asked Questions Is this an original HP cartridge? No — this is a Castle Ink compatible HP 81 (C4930A) replacement, not an HP-branded OEM product. It is engineered to match the original in fit, volume, and print performance. What kind of warranty is included? Every Castle Ink cartridge ships with a one-year quality guarantee. If you have any issue, we'll replace or refund — no questions asked. What is the ink volume? Each cartridge contains approximately 680 mL of black dye ink, matching the OEM HP 81 spec. What if it doesn't work in my printer? Contact our U.S.-based support team and we'll troubleshoot, replace, or refund — no restocking fees, no hassle.