Touch Should the Kobo Touch behave like this ???

I just received my Kobo Touch eReader which is my first ereader

I have switched it on and installed and was paging through the books that came with the device and notice that if I flick a page it takes some time for the new page to show and before this the screen becomes black with white letters before the white page with black letter appears

It is very difficult to explain but I only have experience with reading books on a tablet which is much more fluent and you really have the idea that you read a book and the screen does not become black and then white again

Is there a setting that is not good?

I am not sure if I would like to read a book like this and perhaps the device if broken and I have to return it ???

Looking forward to receive some expert inputs