I take the picture and it comes out white or it turns completely black

I take the picture and it comes out white or it turns completely black

Hi I have a instax mini 70 and I am having a similar problem. I take a picture and it comes out fine.. But the next two or so, I take the picture and it comes out white or it turns completely black. Any ideas of what would be the problem.. it hasn't been exposed. It hasn't been touched incorrectly. I replaced the batteries and that didn't work.. I am not an amateur but this is making me one. Any help please!