diff --git a/sane/scanned_img.h b/sane/scanned_img.h
index 3df550e..6f93bfe 100644
--- a/sane/scanned_img.h
+++ b/sane/scanned_img.h
@@ -114,6 +114,7 @@ class safe_queue
 	std::mutex			lock_;
 	std::vector<TNS>	queue_;
 	size_t				bytes_;
+	T					empty_;
 
 public:
 	safe_queue() : bytes_(0)
@@ -157,6 +158,8 @@ public:
 			if (first)
 				first(t.t);
 		}
+		else
+			t.t = empty_;
 
 		return t.t;
 	}