He was upset by the low quality and high cost of existing patent reproductions, and so he started to develop a system of dry photocopying, which he patented in the late 1930s -- and which became the first dry photocopier that was commercially practical in 1960.
Uzrujavala ga je slaba kvaliteta i visoke cijene postojećih reprodukcija patenata pa je počeo razvijati sustav suhog fotokopiranja, koji je patentirao krajem 1930-ih godina -- i koji je postao prvi suhi fotokopirni aparat koji je bio praktičan za komercijalnu primjenu 1960.