I recently purchased an Epson Artisan 700 multifunction printer to facilitate my prolific photography habits. It is nice to be able to generate high-quality prints for friends or to decorate the walls, and the old Epson PictureMate was a bit limiting, although handy for my annual holiday card photos. Although posting photos online is the most expedient way to share pictures with the world, humans often enjoy tactile experiences, and sending a printed photograph can be very satisfying for my friends and I.
The Artisan is interesting and does a very nice job of printing, but the curious part is the ink cartridges used by this technological marvel. In the past, ink jet printers "guessed" the ink level by perhaps counting the number of times the nozzles were used, or perhaps relying on the end user to observe when various colors ran dry on the output. There is a deeper story on the use of microchips on the ink cartridge to limit the end user's choice on replacement parts and some controversy around whether manufacturers were prematurely reporting an empty cartridge. I'll leave it to you to hunt down that if you're curious.
The Artisan 700 carries six ink cartridges. The pigments are divided into cyan, magenta, yellow, black, light cyan, and light magenta. I ran out of the light cyan color first – and dismantled the cartridge out of curiosity. In the image below, you'll see the piezoelectric sensor and the microchip that connects to the sensor. I was impressed that Epson had chosen to use an actual measurement of the ink level rather than estimating the level, although I suppose if the rate of delivery is consistent from the print head that one could theoretically predict cartridge levels based on counters. Off the top of my head (and I would never blog if I had to do deep research before posting,) I can't think of why the sensor would be superior to estimation unless the print head valves have substantial variance in ink delivery. It's probable, but seems as if the volume delivered would be carefully controlled to ensure the print quality was consistent.
I continued to tear down the ink cartridge until I was satisfied that it was empty. They're still expensive, but I don't feel as if I'm unable to use the full capacity of the cartridge as in previous designs where the printer would declare a cartridge empty before the ink had run out. I expect some of that was a conservative design decision to ensure the flow of ink was reliable for printing, but the marketing department may also play a role in seeking to sell more cartridges rather than providing customer value.
You can learn more about Epson's cartridges from the company at this link.