[FIX] hw_escpos: use logger instead of prints to avoid corrupting the odoo.py command line interface.

addons/hw_escpos/escpos/escpos.py

@@ -6,11 +6,8 @@
 @license: GPL
 '''
 
-try: 
-    import qrcode
-except ImportError:
-    qrcode = None
 
+import logging
 import time
 import copy
 import io
@@ -24,12 +21,19 @@ import xml.dom.minidom as minidom
 
 from PIL import Image
 
+_logger = logging.getLogger(__name__)
+
 try:
     import jcconv
 except ImportError:
     jcconv = None
-    print 'ESC/POS: please install jcconv for improved Japanese receipt printing:'
-    print ' # pip install jcconv'
+    _logger.warning('ESC/POS: please install jcconv for improved Japanese receipt printing:\n  # pip install jcconv')
+
+try: 
+    import qrcode
+except ImportError:
+    qrcode = None
+    _logger.warning('ESC/POS: please install the qrcode python module for qrcode printing in point of sale receipts:\n  # pip install qrcode')
 
 from constants import *
 from exceptions import *