Originally Posted by Tex2002ans
What "compact PDF" most likely does is just run some lossless compression on the scans resulting in no loss in quality. While just exporting as a "normal PDF" would be exporting the uncompressed image files.
I was amazed at how small the "Compact PDF" files come out on Konica-Minolta copiers, so I checked them out a little. A normal PDF output on Konica-Minoltas uses a JPEG-embedded (I think) PDF with typical quality settings for readability and several bits per color component, but "Compact PDF" compresses even further by dropping the bits-per-pixel considerably. I noticed with one document where I had red markings on an otherwise black-and-white document, "Compact PDF" stored the PDF in two layers--a black-and-white layer and a red layer, each one with very few bits per color.