"Description: This article compares the older Canon printers, with the new and latest Pixma TS5050 and TS6050 models, asking how easy they are to refill with ink. We talk about the changes in print head technology and how it effects the end user?"
Middle range Canon printers use five or six separate ink tanks that slot into the printer. This design of these type of Canon printers are generally cheaper to run than the two cartridge versions.
The print heads were once a detachable separate unit that came shipped in the box. Since the introduction of the PGI-550BK CLI-551 BK/C/M/Y ink cartridge system, the print heads are permanently built-into the printer. The principle remains the same, however. To replenish the ink, you only replace the ink tanks. There is no need to buy a new printer head each time, which opens up more possibilities of cheaper ink refills. 
Third party manufacturers can produce the plastic ink tanks far more cheaply, but they still have to overcome the smart-chip problem. Electronics companies have to emulate the software used by Canon for the ink tanks to be accepted in the printers. There is usually a delay of several months while compatible chips are developed, and when they are initially introduced onto the marketplace they are expensive. However, gradually they get cheaper, meaning generic replacement cartridges begin to dramatically reduce the cost of printing. The most recent microchips have been slow to arrive, and have been particularly expensive, but finally prices are beginning to decrease.
Canon ink tanks are divided into two internal sections. One side contains a sponge that soaks up the ink and prevents it from flooding out of the cartridge too quickly. This sponge contacts with the print head, supplying it with a constant flow of ink. The other section is an empty space filled with ink. There is a very small hole connected to the sponge area, allowing ink to gradually flow and saturates the sponge.
The clear compartments in later Canon cartridge versions became smaller, making refilling more difficult. The older PGI-5BK and CLI-8 Cartridges were taller and held more ink than their replacement 520/521 Series and the later 525/526 models. The cartridge design changed slightly with the PGI-550BK Black and CLI-551 Colour Cartridges, making them longer. The trend continued with the 570/571's. Refillable cartridges for Canon Pixma printers work on the same principle. There is a rubber plug that is removed from the top of the cartridge and ink is injected into the open space in the clear chamber. Ink then moves through the small hole and saturates the sponge. Unfortunately it is now only possible to inject approximately 5ml of ink into the clear chamber, and then you have to wait for the ink to filter through to the sponge. Some cartridges are quicker than others to transfer the ink to the sponge, and replacing the plug and shaking the cartridge can speed up the process. It is important to always keep the orange plastic piece on the bottom, otherwise pressure will push ink out of the bottom of the cartridges.
Refillable cartridges for Canon are fitted with auto resetting chips (ARC) which reset back to full on a pretend cycle. The time they reset has nothing to do with how much ink is left inside the cartridge. They estimate the ink usage, similar to original Canon cartridges.
The price of refillable cartridges for recent Canon models has also been unusually high? They are still too expensive to make them a worthwhile investment, but hopefully over the coming months lower prices will make them a viable proposition. So buying a Canon TS5050 or TS6050 printer for refilling purposes is a bad idea at the moment. Fortunately there are still some older Canon printers available that use the older PGI550 and CLI-551 series cartridges. In particular, the Canon Pixma MX725 Printer is a wonderful machine with good print quality and features. A cheaper model, but more difficult to acquire is the Canon Pixma MG5650 Inkjet Printer.
In summary, using refillable cartridges for Canon Pixma 5 and 6 cartridge printers is an acceptable method of refilling, however cartridge capacities may be too small for some users. Refilling original Canon Cartridges can be troublesome, and we do not generally recommend this. Would I buy a Canon 5/6 cartridge printer to refill the cartridges? Maybe yes, if I were an infrequent or modest printer user. A heavy printer user may tire of the small cartridges that required regular refilling.