diff --git a/printlib.php b/printlib.php
index 3d87163..d329895 100644
--- a/printlib.php
+++ b/printlib.php
@@ -7,7 +7,11 @@ define("LF", "\x0a");
 define("PORT", "/dev/usb/lp0");
 function rawlen($data) {
     if (strlen($data)<255 and strlen($data)<MAX_CHAR) {
-        return hex2bin(dechex(strlen($data)));
+        if (strlen($data)<16) {
+            return hex2bin("0" . dechex(strlen($data)));
+        } else {
+            return hex2bin(dechex(strlen($data)));
+        }
     } else {
         return false;
     }