I know this is a common issue from my googles around, but it is VERY frustrating and the remedies that I have seen so far just don't make any difference.
So, the problem seems to be with paper size from what I have seen in other threads, however, I have tried everything I can think of and can see from other threads and it is STILL jamming after every sheet if it is a single page. If it is multiple pages, the first-page prints perfectly fine, the second-page jams about halfway through it. It is easily released.
So, what I have ensured is correct - in admin settings, it is set to A4 (you can also see that even though I have had this printer for over a year, I have barely used it, the toners are the same ones that came with it as I have had this problem since day 1)
In print settings (regardless of which application I use, such as MS Word or printing from the internet, like this screenshot, I ensure that it is A4). I also make sure it is set to A4 on the other Xerox prompt if I open it. 
Page setup Word:
On the printer itself, I set it to white, plain paper at A4 for each tray. The Default is also set to A4 in the menu.
Now, one strange thing that does happen every now and again is that it will come up saying 'Check Bypass paper A4 recycled' and then want to print from the bypass tray, even though there is A4 in tray 1 and it is set on the tabs to A4 paper too.
Any ideas, would be great. I just want to be able to print things!