How can we prevent the physical print-out of invoices for a particular customer?

Hello there!

I wonder if anyone can advise on the following, please?

When invoice print is run (R42565) some customers are set up somehow to prevent a physical print-out of the resulting invoice. (Some customers do not need a paper copy to be produced.)

But we cannot see what setting prevents the invoice from being printed out.

We now have other customers for whom we do not need a physical print-out, so every week the invoices is generated and have to be sifted out and thrown away, which is a waste of time and paper.

From what I know, the only flag that specifies the number of invoice copies printed can be set to a minimum of 1 copy - there's no option for zero copies.