[QUOTE=Higgles;2555208]
Kudos to Higgles for the brilliant diagnosis of the problem !!
I also found that "3DPageFlip PDF to ePub Converter" ( a freeware) solved the [CR] issue : it strips the [CR] in pdf file then converts it to epub .
Everything looks O.K. in my mini Kobo reader now !!
Thanks everyone for comments and advices !