diff --git a/src/escpos/escpos.py b/src/escpos/escpos.py
index ac5f51e..c6ea6bf 100644
--- a/src/escpos/escpos.py
+++ b/src/escpos/escpos.py
@@ -129,7 +129,7 @@ class Escpos(object):
         self.close()
 
     @property
-    def device(self):
+    def device(self) -> object:
         """Implements a self-open mechanism.
 
         An attempt to get the property before open the connection
diff --git a/src/escpos/printer/cups.py b/src/escpos/printer/cups.py
index c7eff06..a870b9b 100644
--- a/src/escpos/printer/cups.py
+++ b/src/escpos/printer/cups.py
@@ -24,6 +24,7 @@ try:
     DEFAULT_HOST = cups.getServer()
     DEFAULT_PORT = cups.getPort()
 except ImportError:
+    print("Error")
     pass
 
 
@@ -81,7 +82,7 @@ class CupsPrinter(Escpos):
         return is_usable()
 
     @dependency_pycups
-    def __init__(self, printer_name=None, *args, **kwargs):
+    def __init__(self, printer_name: str = "", *args, **kwargs):
         """Class constructor for CupsPrinter.
 
         :param printer_name: CUPS printer name (Optional)
diff --git a/src/escpos/printer/file.py b/src/escpos/printer/file.py
index 9eaef9a..5fa24d6 100644
--- a/src/escpos/printer/file.py
+++ b/src/escpos/printer/file.py
@@ -39,7 +39,9 @@ class File(Escpos):
         """
         return is_usable()
 
-    def __init__(self, devfile="/dev/usb/lp0", auto_flush=True, *args, **kwargs):
+    def __init__(
+        self, devfile: str = "/dev/usb/lp0", auto_flush: bool = True, *args, **kwargs
+    ):
         """Initialize file printer with device file.
 
         :param devfile: Device file under dev filesystem
diff --git a/src/escpos/printer/lp.py b/src/escpos/printer/lp.py
index 3ccacfa..02971e9 100644
--- a/src/escpos/printer/lp.py
+++ b/src/escpos/printer/lp.py
@@ -61,7 +61,7 @@ class LP(Escpos):
         """
         return is_usable()
 
-    def __init__(self, printer_name: str, *args, **kwargs):
+    def __init__(self, printer_name: str = "", *args, **kwargs):
         """LP class constructor.
 
         :param printer_name: CUPS printer name (Optional)
diff --git a/src/escpos/printer/network.py b/src/escpos/printer/network.py
index a33c7ff..38e6ddd 100644
--- a/src/escpos/printer/network.py
+++ b/src/escpos/printer/network.py
@@ -9,6 +9,7 @@
 """
 
 import socket
+from typing import Union
 
 from ..escpos import Escpos
 
@@ -50,7 +51,14 @@ class Network(Escpos):
         """
         return is_usable()
 
-    def __init__(self, host, port=9100, timeout=60, *args, **kwargs):
+    def __init__(
+        self,
+        host: str = None,
+        port: int = 9100,
+        timeout: Union[int, float] = 60,
+        *args,
+        **kwargs
+    ):
         """Initialize network printer.
 
         :param host:    Printer's hostname or IP address
diff --git a/src/escpos/printer/serial.py b/src/escpos/printer/serial.py
index 39588c9..8ebc591 100644
--- a/src/escpos/printer/serial.py
+++ b/src/escpos/printer/serial.py
@@ -10,6 +10,7 @@
 
 
 import functools
+from typing import Union
 
 from ..escpos import Escpos
 
@@ -73,14 +74,14 @@ class Serial(Escpos):
     @dependency_pyserial
     def __init__(
         self,
-        devfile="/dev/ttyS0",
-        baudrate=9600,
-        bytesize=8,
-        timeout=1,
-        parity=None,
-        stopbits=None,
-        xonxoff=False,
-        dsrdtr=True,
+        devfile: str = "/dev/ttyS0",
+        baudrate: int = 9600,
+        bytesize: int = 8,
+        timeout: Union[int, float] = 1,
+        parity=None,  # type: str?
+        stopbits=None,  # type: int?
+        xonxoff: bool = False,
+        dsrdtr: bool = True,
         *args,
         **kwargs
     ):
diff --git a/src/escpos/printer/usb.py b/src/escpos/printer/usb.py
index 3295096..b1ee668 100644
--- a/src/escpos/printer/usb.py
+++ b/src/escpos/printer/usb.py
@@ -8,6 +8,7 @@
 :license: MIT
 """
 import functools
+from typing import Dict, Union
 
 from ..escpos import Escpos
 from ..exceptions import USBNotFoundError
@@ -72,12 +73,12 @@ class Usb(Escpos):
 
     def __init__(
         self,
-        idVendor,
-        idProduct,
-        usb_args=None,
-        timeout=0,
-        in_ep=0x82,
-        out_ep=0x01,
+        idVendor: str = "",
+        idProduct: str = "",
+        usb_args: Dict[str, str] = {},
+        timeout: Union[int, float] = 0,
+        in_ep=0x82,  # type: int?
+        out_ep=0x01,  # type: int?
         *args,
         **kwargs
     ):
diff --git a/src/escpos/printer/win32raw.py b/src/escpos/printer/win32raw.py
index e7f18ab..c71fc00 100644
--- a/src/escpos/printer/win32raw.py
+++ b/src/escpos/printer/win32raw.py
@@ -70,7 +70,7 @@ class Win32Raw(Escpos):
         return is_usable()
 
     @dependency_win32print
-    def __init__(self, printer_name=None, *args, **kwargs):
+    def __init__(self, printer_name: str = "", *args, **kwargs):
         """Initialize default printer."""
         Escpos.__init__(self, *args, **kwargs)
         if printer_name is not None: