CISS

A continuous ink system (CIS), also known as a continuous ink supply system (CISS), a continuous flow system (CFS), an automatic ink refill system (AIRS), a bulk feed ink system, or an off-axis ink delivery system is a method for delivering a large and practically unlimited volume of liquid ink to a comparatively small inkjet printhead. Many business and professional grade printers incorporate a continuous ink system in their design to increase the speed and volume of printing capacity. Some aftermarket companies also build retrofit accessories to convert certain models of consumer-grade printers into continuous flow systems.

While such systems, especially third-party retrofitted adapters for home printers, have been frowned upon by most printer manufacturers as they have been seen as a threat to their printers' sales, even going so far as to issuing lawsuits against aftermarket firms, or implementing digital rights management measures in their devices to prevent unauthorised circumvention, some, such as in the case of Epson, have come up with printers equipped with continuous-ink systems,[1] like the L100 and L200 printers, both of which come with a continuous system built in rather than as an add-on adapter. This was seen as a welcome move by users, especially small business owners who rely on bulk-printing solutions, like Internet cafes and small-scale print shops.


Comparison to the tank-on-printhead design

Most low-cost consumer printers place small ink tanks directly on the carriage with the printheads. These tanks can have extremely small liquid volumes, as low as 10 mL, and consequently require frequent replacement. More expensive business-grade printers use progressively larger ink tanks on the printhead, but as the platen width and speed of the printer increases it eventually becomes impractical to have the tanks integrated with the printheads due to the high mass and inertia the liquid volume adds to the printheads and the reduced accuracy of printing that occurs.
Separating the ink storage from the printhead also allows the tank to be refilled or replaced while a print job is in progress. With ink tanks located on the printhead, replacement typically requires repriming and alignment checks that necessarily require aborting any current print job. Separated ink tanks can be refilled or reprimed without disrupting a very large or expensive printing task, such as printing a 2 meter wide by 10 meter long outdoor banner.