The problem with trying to answer your question, AOG, is that computers don't (per se) copy documents. It's the software on your computer which actually does the job and there are lots of different programs which people use. (Fairly obviously, people tend to use the software which comes with their all-in-one printer but there are also lots of other programs which can do the task).
So you need to go into the settings for your particular software and check which settings are currently in use.
Based upon the information in your post I'd guess that you've got 'fit to page' selected somewhere, which automatically removes white edges. (i.e. if you put an A5 document into your scanner the software would ignore the blank space around it and produce an A4 document filled with the text from the A5 page. Your scanner seems to be doing something similar and removing the edges of your A4 pages). You need to change that to 'normal size' (or something similar).
There should also be a 'contrast' setting available for you to change, so that text is no longer as dark as it's currently showing. (Alternatively you might have a 'mono' setting selected, which renders everything on a page as either pure black or pure white, thus eliminating any shades of grey. Switching to a 'colour' setting, even if you're copying a black-and-white document, might help).