Wiping the platen down with a Downy anti static sheet will help a little. If you are on carpet, that is causing the issue. If you can get an anti static mat to put the machine on or move it to a concrete floor that will help. If not, mix some fabric softener and water, 1 to 6 ratio is what we use, and spray the carpet around the machine.
I have also seen people ground their machines from the stand to the outlet but I don't know how much that does to help the problem. The machine is already grounded by default but it can't hurt to try.
Mimaki has an "anti static system" which is just a piece of material that sticks to the back of your machine and slides across the material as it moves through. The material removes the static somehow but not sure what it's made of.