The easiest way would be to record a macro while setting up to print a copy with "Bank Copy" at the header...and printing it.

Then stop the macro,

Press F11 to go to the editor and edit the macro by copying the code between Sub and End Sub and pasting it before End Sub, then change the line that shows "Bank Copy" to "Customer Copy"

Now you can add a button to your spreadsheet that would be linked to this macro and print your 2 copies.