There is a "Print Setup" script step and one of the options in the bottom left is a checkbox callled "Perform without Dialog". First set the specifications in the "Specifcy" button on the bottom right and then checck the "Perform Without Dialog" box and you won't be prompted.
To add to Taylor's response:
Consider putting different versions of this step (i.e. with different settings) into their own scripts, give each script a meaningful name and call the appropriate one(s) in your main script(s), instead of just the bare script step.
This way your scripts read more explicitly, and you have a central place to tweak each setting (well, all the usual benefits of sub-routines).
Thanks for your answer, I'm trying to do that but I didn't found on "print setup properties" dialog the option for setting the scale, may depend on the printer driver?
I'm trying to do that but I didn't found on "print setup properties" dialog the option for setting the scale
Did you select – within a script – the step "Print Setup"? If you don't see an edit field to enter the scale in percent, then it may really depend on the printer driver.
Is the correct one selected? You can change the driver (if you have several printers installed) from the popup menu “Format for”.