Problem with print barcode positions on label

I have develop a web page it contains a Barcode when I want to print the Barcode on the label the first Barcode will print very well  and fitted on the label but for second time and more times the position of the Barcode on the label will be changed and move like the images that selected by red circle , I have no idea what is exact problem

please see the images were attached with this post.

On Google chrome print preview

after print the Barcode the first one is good but the third one and more will move the position of the Barcode

the final result