This article is now over 10 years old and covers Epson’s initial forays into the inclusion of CIS systems in their printers. Their idea was to cling on to cartridges as the ink supply mechanism while using the CIS feed and it worked reasonably well. However it wasn’t without problems as discussed below.
Over the last couple of years it’s become increasingly obvious that the Epson printer design for the PX/TX/Artisan series of printers starting 7xx and 8xx have a major design flaw when it comes to avoiding repetitive clogging or what I would more accurately class as ink starvation issues.
By this I mean that these printers seem particularly prone to air polluting the intenal CIS type design.
The Design?
The problem is that Epson decided to take a leaf from the CIS manufacturers design book and create a printer that keeps the cartridges still and feeds a printhead using tubes. On the face of it a great idea but unfortunately they missed one rather important trick. CIS systems by design do not interrupt the flow of ink to the printhead because the reservoirs are not disconnected from the ink feed loop. Even those that do are designed to allow re-priming to remove any air that leaks into the system be it through ink running too low, or being replaced. Epsons design is completely locked in such that once air is in, it’s very difficult to get it out.
We’ll skip past the bit where Epson blithely ignored the other obvious benefit of CIS systems, ie: greater capacity. It’s doesn’t require a rocket scientist to understand the logic there.
The Problem
Put simply it’s Air, or rather, tiny bubbles of air that either create a blockage in the nozzles or reduce the amount of ink that can flow into them. Effectively they create the same kind of blockage you see
The Cause?
By now you should have realised that every time you change a cartridge you run the risk of introducing a little air into your CIS system and unlike the ink solution itself, air will always rise to the highest point it can so once air has been injected/pulled into the CIS part of the printer system it’s going to be a nightmare to get it out.