Documents printing too small

When I create a document in Writer on my MacBook (MacOSX) it looks fine in my Word Processor window. When I try to print it or to convert it to a PDF it comes out smaller - shrunk by about 30% towards the centre left of the page, with the left margin preserved. This started when I was setting a document up, and has persisted with subsequent documents, and I am unable to work out what adjustments I have changed.
If I convert it to a DOC file and print with Writer it does the same.
However if I then print it using Pages it prints fine.
If I export the document to another computer it prints fine both in Writer and in MS Word there, so it is something in the settings in my own copy of LibreOffice, not something related to the document itself.
I have tried uninstalling and reinstalling LibreOffice to no avail, so the settings must carry over.
Has anyone any idea what I might have tweaked?
Thanks for any help.

Customized settings like this are saved in the user profile, and the user profile is not deleted when you uninstall or upgrade LibreOffice. To get rid of this strange behaviour (I couldn’t find what setting controls it, it may be printer dependent), reset your user profile. See Frequently asked questions - General - The Document Foundation Wiki - important: rename the folder, don’t delete it.

Thanks, floris v; I really appreciate that info. However: There is no LibreOffice User Profile in my ->library->application support folder, though there are plenty of others.
Selecting another printer makes no difference. An ODT file created on another computer prints fine on mine, even if I make a copy of it and alter the copy. As soon as I create a new document on my machine the problem is there, so problem does seem to lie in my user profile settings if I can only find it. I’ll keep trying.

Ah. I’ve found it. It was in my own User files, where the Username->Library folder is a hidden folder and I had to reveal it first, NOT in the HD->Library->Applicationsupport folder. Odd as LibreOffice is installed in the general Apps folder to be used by anyone, but I suppose all Users have different Profiles. Not sure why hidden though! Deleting the libreoffice/4/User folder did the job. Thank you very much indeed. Back to work!