Front Loading Ink Cartridges vs Print Head Ink Cartridges (and Eco Tank)

Jul 11, 2020
I have written quite a number of printer recommendations and in many of them have suggested a printer that takes "front loading" ink cartridges. I want to discuss the benefits and drawbacks of the ink cartridge location and why it makes a difference when you are considering CISS or refillable cartridge solutions.

There are two general locations for locating the ink cartridge in today's ink-jet printers. I'm not talking about true "ink tank" printers, but cartridge-loading printers. They are on top of the print head, and on the front of the printer.

Cartridges on the print head:
Printers where the cartridges are located directly on the print head have one major advantage to the printer manufacturer, and that is simplicity of ink flow. The whole system is essentially gravity fed. Ink from the cartridge flows down either directly into, or through very short hoses into the small reservoir that is inside the print head itself, and from there through the jets onto your paper. In some cases there is no ink pump required at all. In other cases there may be a "hose" type pump that operates by squeezing the ink hoses like this:
On these type of printers there is generally only one pump mechanism that operates on all the ink hoses at once and there is no feedback method to tell the printer when the print head reservoirs are full. Thus the printer only operates the pump when new cartridges are inserted (for the initial "fill" of the print head) or when there is a "deep clean" performed (to eliminate vapour locks). It positions the print head over a waste ink pad to capture any ink squeezed out the nozzles when the pump operates on colours where there is no filling or vapour lock. On these types of printers, the pump doesn't operate to move ink when the printer is actually printing. Only gravity and the very slight "pumping" action of the nozzles spitting tiny ink drops out onto paper are what pulls ink from the cartridge into the head to replenish used ink. Ink is squirted out nozzles that are finer than a hair by the picolitre, so as you might imagine, there is very little suction created by the printing action itself.

CISS: Continuous Ink Supply Systems on Print Head Cartridges
A CISS is an external bottle with tubing that connects that bottle to your ink cartridge. On head-mounted print cartridges remember there is no pump that pulls in ink during normal operation. It is only gravity and the small capillary action suction of ink flowing out of the nozzles that brings ink from the cartridge into the head. With a CISS, there is no pump to bring ink from the external bottle into the cartridge. It is that same gravity and slight capillary action that pulls ink from the external tanks to the internal cartridges. When you add all the extra tubing to connect to an external bottle, it can add a lot of "suction" to the system. This is why when you install a CISS you have to balance the height location of the CISS bottles carefully with the height of the print head. This will help minimize the extra suction that the CISS ink exerts. However, it's almost impossible to balance it perfectly, and even when you do balance it, as the ink level in the external CISS bottles drop, it is harder to pull ink in from the external bottles to the internal cartridges. This can and often does lead to instability in ink flow as the ink drops. In many cases you end up with bad prints as the printer runs into trouble pulling ink into the head, but this clears up as soon as you do a head cleaning since that is the only time a pump forcefully pulls ink in.

Refillable Cartridges on Print Head Cartridges
Refillable cartridges on printers that mount the cartridges on the print head are more reliable than CIS systems. These cartridges gravity feed their ink down to the print head like the original cartridges do. That being said, in most cases these cartridges are not manufactured to the same tolerances as the original ones are, and they must have aftermarket "auto reset" chips in them. Because these cartridges are being tossed around as the print head moves back and forth, in many cases these lower tolerances cause the printer to lose connection with the auto reset chips. This generally interrupts your print and requires you to have to pull the cartridge out and reseat it.

Cartridges on the front:
Now, on to the other kind of printer. Some printers have front-loading ink cartridges. These types of printers have a more complicated ink flow and are often more expensive (to build). Ink from the cartridges has to be moved from the fixed cartridge position to the "holding tank" reservoirs. These reservoirs are still generally in the print head. This ink movement is complicated by the fact that the print head, of course, moves back and forth, so to bring ink from the cartridges requires very long tubes that have to be able to move with the head. Because the ink path is so long, the action of ink being squirted out of the nozzles can't reliably pull ink all the way from the cartridge to the head. Therefore in these type of printers there is generally a separate ink pump for each colour and a feedback mechanism to tell the printer when the reservoir is full. This means the printer can operate each colour pump as required to keep the print head topped up with ink. This is a significant benefit to ink flow.

CISS: Continuous Ink Supply Systems &
Refillable Cartridges on Front-Loading Cartridges

A printer with front-loading cartridges basically is a CIS system. It already has remote bulk ink, and has the added benefit that this ink is pulled in to the internal reservoirs by individual pumps. So generally I don't recommend a CIS system on this type of printer because generally there isn't a lot of value added by this kind of system on a front-loader. If you have a front-loading ink system count yourself lucky and just get refillable cartridges. In many cases you can have the best of both worlds. Some front-loading cartridges are available in an extra-large "extended" version. These extended cartridges generallly stick out the front of the printer and you can visibly see the ink level in it at all times. Some printers with front-loading cartridges DO use very small cartridges and sometimes extended versions of those cartridges aren't available. In cases like this, I might recommend a CISS. But sometimes if this is the case, it means the printer doesn't actually have individual ink pumps. There aren't many printers like this any more, though.

Eco Tank Printers:
So if front-loading ink cartridge printers have individual ink pumps for each colour and a system that uses those pumps to keep the reservoirs topped up, this must mean those really cool (and much more expensive) Eco Tank printers have these pumps too? The answer is not necessarily. One of the first Eco Tank printers was the Epson ET-16500. This printer was basically an Epson WF-7620 with an Epson-manufactured CISS bolted onto the side. That's it. That's all. It's a WF-7620 with a CISS. There are no added pumps. No pumping feedback mechanism. This is why the ET-16500 (and almost all other Epson Eco Tank printers) do NOT use pigment-based inks. Even though the WF-7620 DOES use the Durabrite pigmented inks, when Epson bolted the CISS on the side and rebadged it an ET-16500 they didn't add any pumps and they wanted to maximize the amount of pumping capillary action in the print head, so they use the less viscous dye-based inks.

So whether an Eco Tank printer has those extra pumps of a front-loading-cartridge printer or not depends on the printer engine. Most do not. I haven't done an exhaustive trial of which ones do, and which don't. It's probably a fair bet that if the Eco Tank printer you are considering doesn't use pigment ink, then it's probably a "CISS bolted onto a print-head-mounted-cartridge printer" system internally.

INKvestment Tank Printers:
INKvestment Tank is just a margeting term for Brother's front-loading cartridge system. They claim there is in internal tank that the front-loading cartridge ink gets pumped into. This is true, but it's nothing special. It's just the same pumping action that brings ink from the cartridge to a holding tank (usually in the print head) that almost all front-loading cartridge systems use. It's just the way Brother has of saying their big front-loading cartridges offer a lower price-per page than other printers.

Wrap Up:
To sum it all up, printer with front-loading cartridges are just basically almost always better when it comes to using third party ink. They are more reliable and far less fussy.
Oct 26, 2020
Good article, but it would be nicer if examples (model numbers) of each type was listed. ;)

The "Refillable Cartridges on Print Head Cartridges" category, I assume those would the common Canon design, especially the older models?

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