Each printer has different features and interface. For example, for canon printers and Canon Cli- 251 Ink Cartridges, the ways to use them could be a bit different from the usual.

If you’re wondering why your Canon Cli-251 Ink Cartridges have two black ink tanks, don’t get confused as they serve different purposes for different kinds of printing. The larger tank is for the pigment-based ink exclusively for document printing– particularly if you choose plain paper, do single-sided printing job, or print documents with black text.

On the other hand, the smaller black tank is for dye-based ink made for printing pictures, doing double-sided or duplex printing jobs, and printing using papers other than the plain paper, like

labels, photo paper, envelopes, and so on. You can also print webpages and PDF files better with the smaller black ink tank.

Thus, if your small blank ink tank no longer has ink, you can’t use the larger one in its place. However, there’s a workaround—you can highlight the text and change it to black text if it isn’t yet, so you can print using the larger black tank. On the other hand, if your larger black ink tank runs out, you can use the smaller tank if you change the color of the text to other colors apart from black.

Furthermore, if you no longer have ink supply and want to avoid the low ink warnings that pop up, you can temporarily disable the detection function by pressing the stop or reset button for about 7 seconds. The ink level detection function will instantly be re-enabled once the ink tanks are refilled.