If there is a self destruct after one year then there must be a real time clock of some sort, if it's a clock chip then it should be possible to intercept the clock reference by either changing the clock oscillator Cristal for one that has a frequency of 1/2 or 1/4 of the original. If the clock reference is taken from another reference the inserting a device by 2 or 4 IC would do the same. Another option could be to remove the clock backup power source is battery then the clock would always start with its default date/time it just depends on wether the full data time are used or just the day.
My preference would be to use a slower clock reference signal. When I get my printer (just ordered printer) I will look and see if I can find the if there's clock, it could be in the printer or in the cartridge.
Anyone got a view to this approach to extending the usable life of a cartridge.