Most of the scanning software allows you to set a naming convention for saving files in the preferences/set-up. Simply set it matching the first Invoice No. before scanning. Note that if you scan anything else you will need to reset the file name preferences to match the Invoice. Usually the software will prompt you to confirm the file name. When batch scanning a number of documents you only need to confirm the file name when saving the first file. The rest will increment automatically.
Acrobat's OCR function is great for changing an image PDF to a searchable PDF.
Look a Epson or Microtek (if they are still made). Most come with their own scanning and OCR software.
cacman wrote: