Check with your local dealer, I’m sure they can sell you flush.
Maybe you can get the print heads going. But it will be a hard work. I don’t know how long the machine has standing still. But I have customer printer standing still for 2 weeks and all nozzles gone on all print heads. I think I needed to work on it for 4 days to get all printed working.
Good luck to get it going again
You can contact Canon directly or any number of UV ink suppliers. Most flush liquid is similar and will do the same job.Where can I buy the flush?