Changing a number in each time I print

You need a macro for that. I found the following macro and made some changes on it. Try it to see if it works correctly:

Sub PrintCopies_ActiveSheet()

Dim CopiesCount As Long
Dim copynumber As Long

CopiesCount = Application.InputBox("How many copies do you want?", Type:=1)
'Now the program wants you to input how many pages you like to print.
'You can input 100 here.

For copynumber = 1 To CopiesCount
With ActiveSheet
   .Range("E1").Value = copynumber 'I assume your invoice number is in cell E1.
   .PrintOut 'Print the sheet
End With
Next copynumber
End Sub

I would use a macro to do this, as there doesn't seem to be an easy, built in method of doing this. The outline of the macro would be pretty simple. Something of this nature:

1. Prompt for number of copies and printer name
2. Set The invoice Number cell to 0
3. Loop for number of copies
   1. Increment the invoice cell number
   2. Print the document to printer name

Edit

This page has an example of it for Word, so you could just adapt this to excel. This page has a rough example for excel