Paper-Folding machinery is used for numerous purposes in the stationery trade, apart from its application to the folding of sheets for the bookbinder. Devices for folding come most prominently forward in connexion with the envelope manufacture, an industry which received an enormous development by the introduction of uniform postage rates. In envelope-making the folding is commonly associated with gumming, and sometimes with embossing, in the same system of machinery. The first efficient automatic machine for envelope manufacture was devised by Edwin Hill and Warren de la Rue, and by them patented in 1845. Many forms of envelope folding and gumming machine now exist. In making envelopes the blanks are first cut out by shaped cutters or punches acting at one stroke on a thickness of from 200 to 300 sheets of paper. These blanks in the latest form of machine are gummed by a pad which takes gum from a roller and presses it on the edges of the paper, just as printing ink is received from cylinders and pressed on paper in printing. The gummed surface of the pad lifts each blank separately, places it under a plunger, which, descending, passes it to folders, whence it is delivered into a clip in an endless band of considerable length. The envelopes are delivered into the clips in the band at the rate of about 100 to 150 per minute.

Perforating and Punching give rise to a range of machines of varied form and complexity. The idea of perforating paper so as to allow of the ready detaching of portions by tearing was conceived and. patented in 1848 by Mr Henry Archer. Of such utility was Mr Archer’s conception deemed by the post-office authorities as a convenience for detaching stamps from sheets that in 1853 he was awarded £4000 for his patent rights. The applications of perforation are now very numerous, but its value still remains most obvious in connexion with the detachment of adhesive stamps from sheets.

Numbering and Paging constitute another series of stationery operations, for which ingenious machines have been devised. For consecutive numbering a series of printing disks are employed, on the periphery of which the series of digits 1 to 0 are raised. The outer disk moves a number after each impression, the second disk moves once in ten times, and so on, thus automatically imprinting consecutive numbers up to the limit of the disks on the machine. Such a machine prints only on one side of the paper, and where the numbering is required on both sides the disks must be geared to move two places, numbering only odd or even numbers, two printings being thus required. For printing right and left consecutively an endless band machine is used, which prints alternately below and above for the two sides of the sheet.