Printing electronics technology is not new. The idea of using inkjet printer with special ink for printing circuit has been around for a while and has led to a number of electronic circuit printers that are used to print "simple" electronic devices, like RFID tag.
As one might expect technology is moving forward and as usual progress can be measured on several axes: cheaper, smaller, more performant, more sophisticated.
And here we have an example in a news coming from Palo Alto where researchers have managed to print the electronics required to develop an X-ray sensor, like the ones you are seeing at your dentist's shop, just much smaller!
Researchers at Palo Alto Research Centre have shown the result of their work at the AVS Conference that was held on November 9-14-2014, in Baltimore. They have exploited the capabilities of inkjet printers to print on a variety of surfaces, including plastic foils, to print an X-ray sensor that is light and portable and thus can be used in the field, by doctors or for security screening (including bomb detection).
This news is interesting since it shows the progress that are being made towards more and more complex circuits. An X-ray sensor array is clearly much more complex than an RFID circuit. At the same time it is several orders of magnitude less complex than the circuits we have in our cell phones and there is no expectation to see these kinds of circuits printed in the future.
Yet, printed electronics can evolve rapidly to serve many areas where there is no real need for millions of transistors, like bio chips that can be printed on the skin to monitor some health parameters and the antennas letting the chip communicate with a nearby device (like a cell phone).