--kiosk-printing effecting all chrome instance

I am using the --kiosk-printing with the --app=myApp option - in order to print automatically.

The problem is - that if from one hand - I afterwards open a different instance of Chrome - also over there the printing will be automatically. and on the other hand - if there is already instance of chrome open - the kiosk-printing doesnt work.

Any ideas for help? Thanks!