To eliminate the drawbacks of the conventional fax machines, this paper proposes a new paperless fax machine equipped with a single-touch panel, replacing the scanning and the printing units which not only take up most space but also are the most costly and vulnerable parts. In the proposed paperless fax machine, a received fax can be displayed and, if necessary, signed directly on the touch panel. The digital signature is then pasted onto the fax document, which can be sent back or stored in the memory for future references. Besides, a real handwriting reconstruction is developed to make the appearance of the digital signature close to real handwriting on the single-touch panel.