diff --git a/escpos/__init__.py b/escpos/__init__.py
index 8f74f5c..1d72614 100644
--- a/escpos/__init__.py
+++ b/escpos/__init__.py
@@ -1,2 +1,5 @@
-import constants, escpos, exceptions, printer
+import constants
+import escpos
+import exceptions
+import printer
 __all__ = ["constants", "escpos", "exceptions", "printer"]
diff --git a/escpos/cli.py b/escpos/cli.py
index 6f1df41..1a52dcb 100755
--- a/escpos/cli.py
+++ b/escpos/cli.py
@@ -46,9 +46,11 @@ __license__ = "MIT"
 import re
 
 from escpos import printer
+
 epson = printer.Usb(0x0416, 0x5011)
 # TODO: Un-hardcode this
 
+
 def _print_text_file(path):
     """Print the given text file"""
     epson.set(align='left')
@@ -56,10 +58,12 @@ def _print_text_file(path):
         for line in fobj:
             epson.text(line)
 
+
 def _print_image_file(path):
     """Print the given image file."""
     epson.fullimage(path, histeq=False, width=384)
 
+
 def print_files(args):
     """The 'print' subcommand"""
     for path in args.paths:
@@ -74,6 +78,7 @@ def print_files(args):
 KNOWN_BARCODE_TYPES = ['UPC-A', 'UPC-E', 'EAN13', 'ITF']
 re_barcode_escape = re.compile(r'^%(?P<type>\S+)\s(?P<data>[0-9X]+)$')
 
+
 def echo(args):  # pylint: disable=unused-argument
     """TTY-like line-by-line keyboard-to-printer echo loop."""
     try:
@@ -94,6 +99,7 @@ def echo(args):  # pylint: disable=unused-argument
 
 from PIL import Image, ImageDraw
 
+
 def _stall_test(width, height):
     """Generate a pattern to detect print glitches due to vertical stalling."""
     img = Image.new('1', (width, height))
@@ -101,6 +107,7 @@ def _stall_test(width, height):
         img.putpixel(pos, not sum(pos) % 10)
     return img
 
+
 def _test_basic():
     """The original test code from python-escpos's Usage wiki page"""
     epson.set(align='left')
@@ -120,24 +127,26 @@ def _test_basic():
     # Cut paper
     epson.cut()
 
+
 def _test_barcodes():
     """Print test barcodes for all ESCPOS-specified formats."""
     for name, data in (
-        # pylint: disable=bad-continuation
-        ('UPC-A', '123456789012\x00'),
-        ('UPC-E', '02345036\x00'),
-        ('EAN13', '1234567890128\x00'),
-        ('EAN8', '12345670\x00'),
-        ('CODE39', 'BARCODE12345678\x00'),
-        ('ITF', '123456\x00'),
-        ('CODABAR', 'A40156B'),
-        # TODO: CODE93 and CODE128
+            # pylint: disable=bad-continuation
+            ('UPC-A', '123456789012\x00'),
+            ('UPC-E', '02345036\x00'),
+            ('EAN13', '1234567890128\x00'),
+            ('EAN8', '12345670\x00'),
+            ('CODE39', 'BARCODE12345678\x00'),
+            ('ITF', '123456\x00'),
+            ('CODABAR', 'A40156B'),
+            # TODO: CODE93 and CODE128
     ):
         # TODO: Fix the library to restore old alignment somehow
         epson.set(align='center')
         epson.text('\n%s\n' % name)
         epson.barcode(data, name, 64, 2, '', '')
 
+
 def _test_patterns(width=384, height=255):
     """Print a set of test patterns for raster image output."""
     # Test our guess of the paper width
@@ -152,6 +161,7 @@ def _test_patterns(width=384, height=255):
     epson.image(_stall_test(width, height))
     epson.image(_stall_test(width / 2, height))
 
+
 def test(args):
     """The 'test' subcommand"""
     if args.barcodes:
@@ -161,6 +171,7 @@ def test(args):
     else:
         _test_basic()
 
+
 # }}}
 
 def main():
@@ -168,25 +179,26 @@ def main():
     # pylint: disable=bad-continuation
 
     import argparse
+
     parser = argparse.ArgumentParser(
         description="Command-line interface to python-escpos")
     subparsers = parser.add_subparsers(title='subcommands')
 
     echo_parser = subparsers.add_parser('echo', help='Echo the keyboard to '
-        'the printer line-by-line (Exit with Ctrl+C)')
+                                                     'the printer line-by-line (Exit with Ctrl+C)')
     echo_parser.set_defaults(func=echo)
 
     print_parser = subparsers.add_parser('print', help='Print the given files')
     print_parser.add_argument('--images', action='store_true',
-        help="Provided files are images rather than text files.")
+                              help="Provided files are images rather than text files.")
     print_parser.add_argument('paths', metavar='path', nargs='+')
     print_parser.set_defaults(func=print_files)
 
     test_parser = subparsers.add_parser('test', help='Print test patterns')
     test_modes = test_parser.add_mutually_exclusive_group()
     test_modes.add_argument('--barcodes', action='store_true',
-        help="Test supported barcode types (Warning: Some printers must be "
-        "reset after attempting an unsupported barcode type.)")
+                            help="Test supported barcode types (Warning: Some printers must be "
+                                 "reset after attempting an unsupported barcode type.)")
     test_modes.add_argument('--patterns', action='store_true',
                             help="Print test patterns")
     test_parser.set_defaults(func=test)
@@ -194,6 +206,7 @@ def main():
     args = parser.parse_args()
     args.func(args)
 
+
 if __name__ == '__main__':
     main()
 
diff --git a/escpos/escpos.py b/escpos/escpos.py
index 007c3b1..3a8c39a 100644
--- a/escpos/escpos.py
+++ b/escpos/escpos.py
@@ -15,10 +15,8 @@ except ImportError:
     from PIL import Image
 
 import qrcode
-import time
 import textwrap
 import binascii
-import os
 import operator
 
 from .constants import *
@@ -26,6 +24,7 @@ from .exceptions import *
 
 from abc import ABCMeta, abstractmethod  # abstract base class support
 
+
 class Escpos(object):
     """ ESC/POS Printer object
 
@@ -64,9 +63,9 @@ class Escpos(object):
         else:
             image_border = 32 - (size % 32)
             if (image_border % 2) == 0:
-                return (round(image_border / 2), round(image_border / 2))
+                return round(image_border / 2), round(image_border / 2)
             else:
-                return (round(image_border / 2), round((image_border / 2) + 1))
+                return round(image_border / 2), round((image_border / 2) + 1)
 
     def _print_image(self, line, size):
         """ Print formatted image
@@ -221,16 +220,16 @@ class Escpos(object):
         #self._raw(binascii.unhexlify(buf))
         for y in range(height):
             for x in range(width):
-                value = image.getpixel((x,y))
-                value = (value << 8) | value;
+                value = image.getpixel((x, y))
+                value |= (value << 8)
                 if value == 0:
                     temp |= mask
 
-                mask = mask >> 1
+                mask >>= 1
 
                 i += 1
                 if i == 8:
-                    buf +=   ("%02X" % temp)
+                    buf += ("%02X" % temp)
                     mask = 0x80
                     i = 0
                     temp = 0
@@ -413,7 +412,7 @@ class Escpos(object):
         :param columns: amount of columns
         :return: None
         """
-        colCount = self.columns if columns == None else columns
+        colCount = self.columns if columns is None else columns
         self.text(textwrap.fill(txt, colCount))
 
     def set(self, align='left', font='a', text_type='normal', width=1, height=1, density=9):
diff --git a/escpos/exceptions.py b/escpos/exceptions.py
index 0a24ffc..61319df 100644
--- a/escpos/exceptions.py
+++ b/escpos/exceptions.py
@@ -153,6 +153,7 @@ class CharCodeError(Error):
     def __str__(self):
         return "Valid char code must be set"
 
+
 class USBNotFoundError(Error):
     """ Device wasn't found (probably not plugged in)
 
diff --git a/escpos/printer.py b/escpos/printer.py
index 1f95665..f149c2e 100644
--- a/escpos/printer.py
+++ b/escpos/printer.py
@@ -13,7 +13,6 @@ import serial
 import socket
 
 from .escpos import *
-from .constants import *
 from .exceptions import *
 
 
@@ -32,7 +31,7 @@ class Usb(Escpos):
         :param out_ep: Output end point
         """
         Escpos.__init__(self, *args, **kwargs)
-        self.idVendor  = idVendor
+        self.idVendor = idVendor
         self.idProduct = idProduct
         self.interface = interface
         self.in_ep = in_ep
@@ -100,10 +99,10 @@ class Serial(Escpos):
         :param dsrdtr:   Hardware flow control (False to enable RTS/CTS)
         """
         Escpos.__init__(self, *args, **kwargs)
-        self.devfile  = devfile
+        self.devfile = devfile
         self.baudrate = baudrate
         self.bytesize = bytesize
-        self.timeout  = timeout
+        self.timeout = timeout
         self.parity = parity
         self.stopbits = stopbits
         self.xonxoff = xonxoff
@@ -208,9 +207,9 @@ class File(Escpos):
         :param msg: arbitrary code to be printed
         """
         if type(msg) is str:
-            self.device.write(msg.encode());
+            self.device.write(msg.encode())
         else:
-            self.device.write(msg);
+            self.device.write(msg)
 
     def __del__(self):
         """ Close system file """
diff --git a/setup.py b/setup.py
index a68987d..bbb4dc5 100755
--- a/setup.py
+++ b/setup.py
@@ -5,10 +5,12 @@ import sys
 from setuptools import setup
 from setuptools.command.test import test as TestCommand
 
+
 def read(fname):
     """read file from same path as setup.py"""
     return open(os.path.join(os.path.dirname(__file__), fname)).read()
 
+
 class Tox(TestCommand):
     """proxy class that enables tox to be run with setup.py test"""
     user_options = [('tox-args=', 'a', "Arguments to pass to tox")]
@@ -26,7 +28,7 @@ class Tox(TestCommand):
 
     def run_tests(self):
         """run tox and pass on user-options"""
-        #import here, cause outside the eggs aren't loaded
+        # import here, cause outside the eggs aren't loaded
         import tox
         import shlex
         args = self.tox_args