You are using these machines very hard ( In a continuous commercial setting) and you need to be aware of what to do to ease up on the requirements. If you have tried OEM cyan and the problem is "not as bad" then you need to do a couple things. The not as bad might be because the cart is flowing perfectly BUT there is an underlying issue with a film already on the heater.
First...it is required to identify the problem and understand what caused it.
When ink flow is compromised, you start developing a coating on the heaters inside the nozzle. This coating prevents the heater from proper cooling and in facts acts as an insulative layer. So on long heavy jobs when the heaters are working real hard boiling ink out, as soon as you start having the smallest of flow problems you start building up an insulative layer. Once this layer is there and even if you switched to a perfect cartridge, you run the risk that the layer will continue to build up EVEN with a new cartridge.
You need to understand that once the insulative layer appears, the situation can SPIRAL and build exponentially. Here's why. Once the film builds up, it insulates. This insulative layer causes the heater to get hotter. Once it gets hotter it causes the coating to build more and so on.
So suppose you have problems, and use the power clean trick to "clean" the nozzles by flushing with Pharmacists solution. You need to make sure that when it is clean...it is really clean because any remaining deposits there and then subjected to heavy load in that color will cause the same thing to occur again. Here's the thing, once you need to use Pharmacist's solution to clear a head.....it is indicative that you have an underlying problem.
If a small film is there and you continue to print lightly or use the nozzles lightly, then you might find that over time the film "can " actually dissolve and the heater is back good again. In a home setting this can happen. In a commercial setting this is not likely to happen.
Again the key thing is to recognize that the problem was ink flow and once the film builds and subjected to the same heavy load again and again....you are going to have problems.
Now in a production environment where images are repeated over and over and over, for hours on end....you NEED to have carts flowing perfectly AND you need to maintain those carts on a regular basis. There should be NO shortcuts in trying to maximize the useage of the cart till it shows flow problems. By then, your printhead has already built up a good coating on the heaters. So you will need to determine exactly when carts must be pulled and flushed BEFORE ANY problems begin. Think of maintaining a fleet of vehicles...you do not repair them when they break. You must maintain them BEFORE they break so that they don't break. Same thing here.
How to do that? Believe or not some have determined this aspect to a fine science. They know when to pull a set of carts for flushing by weighing the carts AFTER filling and seeing how much ink it will take. Once they cannot absorb or take up a certain amt of ink, they are pulled for maintenance BEFORE they give problems. How much are the weights...that is proprietary data for that printing house but with this method, I am told that using the PC inks, the machine breaks from ink pad filling before the printhead ever needs to be maintained. Printheads do not need to be maintained for the life of the machine. Prior to this they were having hell keeping the printer going until they learned of what I divulged about refilling BEFORE empty. The refill at low or before was a "GAME CHANGER" for them and once they recognized that ink flow MUST be perfect in a commercial setting then the world changed. BTW they run more machines than you are running for longer hours and possibly more days per week. Some on this forum will know who they are but they made refilling into a science and possibly they possibly takes the Guinness world record if it was ever kept.
The very problem you are experiencing is intrinsically what happens with CISS units on Canons. The above also indicates that flushing carts BEFORE they give signs of problems is a must in a commercial setting if you don't want downtime. For the home user, this is not that critical but in a commercial setting printing the SAME heavy load over and over you will need to rethink what needs to be done and change procedure appropriately. All they needed as I had advised them was a visit to Home Depot, some tube, fittings and a run to Walmart or Canadian Tire for a food dehydrator and air compressor. Less than a couple hundred and it changed their world.
The other thing that needs to be done is to review the artwork and see if you can reduce the saturation of the image. You'd be surprised at how much less reducing the saturation will affect the load on a nozzle. This has a larger effect than you might think...a slightly less vibrant picture will ease the load dramatically on the printhead. Depending on the media setting used, this might also assist by spreading the load to other nozzles as well. So two things would happen...less ink demanded by the Cyan AND spreading the load to other carts on lighter tones.
To answer your question, no it is as you have determined, not the ink but the condition of the carts and possibly a not perfectly functioning printhead heater and finally a tweak to the printed image.
