Code 128 is a good one to use. You can perform this one by resizing you rtf template print area. In play store we have the scanner apps, install the same in your phone then get the print out of your output then scan it your own for testing and you got the final answer repeating the same.

Before resizing that, put * before and after of your bar code column. If you have already done this then go with the above one.

Which code you are using to print a Bar code. If you have more characters in bar code then expand the text area which is used print the barcode in your template. Even though for a better reading you can resize your print area and check repeat the same unitil it is readable.