Our standard conductive ink takes 30 minutes to cure, the additional 20 minutes is accounted for the heater to cool down. I have had mixed results with curing for shorter periods of time - in some cases I’ve had solderable ink at 12 minute cure times, but it wasn’t particularly consistent. I can say that the conductivity of the ink itself is mostly set within the first 5 minutes of curing, the rest of the curing time will ensure the resin that binds the ink together is properly set. So, it may be possible to solder to ink that’s been cured for a shorter period if the ink layer is relatively thin, though the mechanical stability might not be up to scratch.
If you’d like to try it out, best I can say is to give it a go and let us know what you find!