diff --git a/escpos/constants.py b/escpos/constants.py
index 4274fbe..704f167 100644
--- a/escpos/constants.py
+++ b/escpos/constants.py
@@ -10,6 +10,11 @@ moved to `capabilities` as in `escpos-php by @mike42 <https://github.com/mike42/
 :license: GNU GPL v3
 """
 
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+#from __future__ import unicode_literals
+
 # Control characters
 # as labelled in http://www.novopos.ch/client/EPSON/TM-T20/TM-T20_eng_qr.pdf
 NUL = '\x00'
diff --git a/escpos/escpos.py b/escpos/escpos.py
index 0105c61..b55ee12 100644
--- a/escpos/escpos.py
+++ b/escpos/escpos.py
@@ -9,6 +9,11 @@ This module contains the abstract base class :py:class:`Escpos`.
 :license: GNU GPL v3
 """
 
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+#from __future__ import unicode_literals
+
 try:
     import Image
 except ImportError:
@@ -63,9 +68,9 @@ class Escpos(object):
         else:
             image_border = 32 - (size % 32)
             if (image_border % 2) == 0:
-                return round(image_border / 2), round(image_border / 2)
+                return image_border // 2, image_border // 2
             else:
-                return round(image_border / 2), round((image_border / 2) + 1)
+                return image_border // 2, (image_border // 2) + 1
 
     def _print_image(self, line, size):
         """ Print formatted image
diff --git a/escpos/exceptions.py b/escpos/exceptions.py
index 56a30a4..a31a304 100644
--- a/escpos/exceptions.py
+++ b/escpos/exceptions.py
@@ -20,6 +20,11 @@ Result/Exit codes:
 :license: GNU GPL v3
 """
 
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+#from __future__ import unicode_literals
+
 
 class Error(Exception):
     """ Base class for ESC/POS errors """
diff --git a/escpos/printer.py b/escpos/printer.py
index 88ce042..85eb553 100644
--- a/escpos/printer.py
+++ b/escpos/printer.py
@@ -7,6 +7,11 @@
 :license: GNU GPL v3
 """
 
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+#from __future__ import unicode_literals
+
 import usb.core
 import usb.util
 import serial