diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index 8822a39b87..885d0621e0 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -402,7 +402,7 @@ class HTMLPreProcessor(object):
                   (re.compile(r'((?<=</a>)\s*file:/{2,4}[A-Z].*<br>|file:////?[A-Z].*<br>(?=\s*<hr>))', re.IGNORECASE), lambda match: ''),
 
                   # Center separator lines
-                  (re.compile(u'<br>\s*(?P<break>([*#•✦=]+\s*)+)\s*<br>'), lambda match: '<p>\n<p style="text-align:center">' + match.group(1) + '</p>'),
+                  (re.compile(u'<br>\s*(?P<break>([*#•✦=] *){3,})\s*<br>'), lambda match: '<p>\n<p style="text-align:center">' + match.group('break') + '</p>'),
 
                   # Remove page links
                   (re.compile(r'<a name=\d+></a>', re.IGNORECASE), lambda match: ''),