If I understand correctly, you are storing the data in a text file, right?
What application do you use to print the text data? If other than LV, you should be able to set the font size..
If using LV and printing directly from the running vi, you can try the following.
At some point in the vi, you may display the text as an indicator and call it something (ex: data_tobe_printed)
Right click the indicator and select Create > Property Node.
Use the finger pointer and click on the newly created property node. Select => Text => Font => Size
Change the property node to Write (right-click select "Change to Write") and wire the number 10 to it.
You can also do the same to choose another font type, etc.
Hope this helped.
JLV