I have a Canon printer/scanner and a Canon scanner.  Both of them have software that allows you to scan to a file.  A pdf file.  When scanning to a pdf file they ask if there is another page.  Answer yes and insert the next page to copy.

I suspect that the Lexmark will have software that allows the same thing. When you scan you might set the dpi to 150 which should be adequate.  It should create a smaller file.

A little expirmentation might be in order.