diff --git a/src/printer/posprinter.cpp b/src/printer/posprinter.cpp
index 38333ed..9ff4dec 100644
--- a/src/printer/posprinter.cpp
+++ b/src/printer/posprinter.cpp
@@ -12,12 +12,12 @@
 #include <string>
 
 const std::string PosPrinter::Command::RESET = {0x1b, 0x40};
-const std::string PosPrinter::Command::ENCODING = {'\x1b', '\x74', 16};
-const std::string PosPrinter::Command::CENTERING = {'\x1b', '\x61', '\x01'};
+const std::string PosPrinter::Command::ENCODING = {0x1b, 0x74, 16};
+const std::string PosPrinter::Command::CENTERING = {0x1b, 0x61, 0x01};
 const std::string PosPrinter::Command::LEFT_ALIGN = {0x1b, 0x61, 0x00};
 const std::string PosPrinter::Command::RIGHT_ALIGN = {0x1b, 0x61, 0x02};
-const std::string PosPrinter::Command::FONT_SIZE_BIG = {'\x1b', '\x21', '\x10'};
-const std::string PosPrinter::Command::FONT_SIZE_NORMAL = {'\x1b', '\x21', '\x00'};
+const std::string PosPrinter::Command::FONT_SIZE_BIG = {0x1b, 0x21, 0x10};
+const std::string PosPrinter::Command::FONT_SIZE_NORMAL = {0x1b, 0x21, 0x00};
 const std::string PosPrinter::Command::FEED = {0x1b, 0x64, 0x03};
 
 PosPrinter::PosPrinter()