Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
What version of MAC OS X is on your iMac?
If the driver does not fit the version on your iMac, then it may not quite work, in the way you have reported.
Is your question about when Canon will release a driver version for your printer model, that matches the MAC OS X version on your iMac? I could not say myself. That would be a question to ask Canon themselves. And if your printer is old enough, Canon may never bother to write a more modern version of the printer driver or software, owing to decreased demand and fewer printers in service... to small a market share in short.
But writing to Canon will add your little bit to the total, and encourage them to view that model # ***** worth supporting.
How old is your printer? if older than 6 to 8 years old, then chances are very small that it will have a driver released for more modern versions of MAC OS X.