Following Robert's successful model, built in 1798, Saint-Léger Didot insisted that Robert apply for a patent. Prior to 1798, paper was made one sheet at a time, by dipping a rectangular frame or mould with a screen bottom into a vat of pulp. The frame was removed from the vat, and the water was pressed out of the pulp. The remaining pulp was allowed to dry; the frame could not be re-used until the previous sheet of paper was removed from it. Robert's construction had a moving screen belt that would receive a continuous flow of stock and deliver an unbroken sheet of wet paper to a pair of squeeze rolls. As the continuous strip of wet paper came off the machine it was manually hung over a series of cables or bars to dry. With Didot's urging, Robert and Didot went to
François de Neufchâteau, the
Minister of the Interior and applied for a patent. In 1799, the patent ''(brevet d'invention)'' was granted by the French Government, for which Robert paid 8,000 francs. The patent specification and application for the continuous paper-making machine is published in the second volume of the ''Brevets d'Inventions Expirés''. On 9 September 1798 (23
Fructidor Year VI) Robert wrote a letter applying for a patent: De Neufchâteau authorised the Bureau of Arts and Trades
(Bureau des Arts et Métiers) to send a draughtsman, Monsieur Beauvelot, to Essonnes to document and build an improved model. The minister also authorised a member of the
Conservatoire National des Arts et Métiers to accompany him. The
Bureau des Arts et Métiers then declared: The
Conservatoire des Arts et Métiers paid Robert three thousand francs to build another model for permanent display at the
Musée des Arts et Métiers. In 1785,
Christophe-Philippe Oberkampf invented the first machine for printing dyes on squares of
wallpaper. The significance of Robert's invention was for more than mechanising a labour-intensive process, in also allowing continuous lengths of patterned and coloured paper to be produced for hanging. This offered the prospect of novel designs and nice tints to be printed and displayed in drawing rooms across Europe. ==Development in England==