This error came out of the blue. When the On button is pressed, the green light flashes and after a time both the Resume button and On button flash alternately. No amount of un and replugging the power and USB cables makes any difference. Drivers reinstalled.
The 6C10 error has been variously described as both a "Reset Canon Printer ink absorber" error or a "Valve Cam Sensor" error. I don't know where the valve cam sensor is located and I've found little info on the net. They say this sensor could be blocked by paper debris but I have no way of telling.
This printer was bought new, has had relatively little use and mainly serves to print CDs/DVDs.
There's a foam strip running almost the full width inside the printer and it looks 95% clean. I don't know if that's the "ink absorber".
There is a button-push sequence designed to place the iP4600 into service mode, where you can reset the ink absorber but so far this has done nothing.
If anyone here has some know how, your input is much appreciated!