Some printers do that, it is very expensive and mostly moot because of electronic documents. See https://qz.com/1002927/computer-printers-have-been-quietly-emb

Some printers do that, it is very expensive and mostly moot because of electronic documents. See https://qz.com/1002927/computer-printers-have-been-quietly-embedding-tracking-codes-in-documents-for-decades/ https://qz.com/1002927/computer-printers-have-been-quietly-e...