I'm currently using a Brother MFC7840-W which is good, except for problems with the toner & drum sensors acting up sometimes.  I have a full version of Adobe Acrobat.  It will turn a .tif into a .pdf as expected. Some free apps also do this.  But Acrobat is not a part of the scanner program.

I believe some multifunction machines create a .pdf as they scan, rather than running an extra process on the computer, after the scan is complete.  Do the HPs or Samsungs do this?