Sorry I left that out - it was 128. Here is the event handler code:
private static void HandleMergeImage(Object sender, MergeImageFieldEventArgs e)
{
if(e.get_FieldName().equals("barcode_data"))
{
// Find out if a barcode is needed for row and find out the row
int recordNum = e.get_RecordIndex();
// Get the requested barcode, skipping the first, label, row
String bcRequested = cells.get_Item(recordNum+1, 2).get_StringValue();
// Set blank image if there is no requested barcode
if (bcRequested.charAt(0) == ' ')
{
e.set_ImageFileName(blankImageName);
return;
}
BarCodeBuilder bb = new BarCodeBuilder();
// Set the Code text for the barcode
bb.set_CodeText("71040343386001192576");
// Drop the text from the code image
bb.set_CodeLocation(CodeLocation.None);
// Set size to .75 - .8 inch
bb.set_BarHeight(20.0f); //20 mm. printed
// Remove border
bb.set_BorderVisible(false);
// Set small bar/space width to 16 mils
bb.set_xDimension(0.406f); // .406 mm. printed
// Set the symbology type to Code128
bb.set_SymbologyType(Symbology.Code128);
// Pass the image to the document merge
e.set_Image(bb.get_BarCodeImage());
}//if(e.get_FieldName().equals("barcode_data"))
}