I use card stock for my script and I have a problem with the back of the pages get smudgy from the copied page behind it. I don't know if this has something to do with the paper itself or if it's just the toner in the copier. It erases, but that's a pain and very time consuming. And on top of that, it's a little annoying writing blocking on less than perfect paper. Has anyone else run into this problem? Is there anything I can do to prevent it? Thoughts?