Barcodes sometimes cant be bleeped/scanned using barcode gun

Hi ALl

I have written VBA code to copy data from Access to Ms word and when i print off the word document then I use barcode gun to bleep the barcodes which are on the Pages. So sometimes I can bleep the barcodes very quickly and sometimes it can't be bleeped. I have got a paper in front of me in which there are 3 or 4 barcodes. I can't bleep them very quickly. sometimes it have to keep on trying until they cant be bleeped and sometimes they get bleeped straightway.

Please see attached the mail merge word document.

ANy ideas what shall i do?

Thanks