A self-mailer is conventionally defined as a mailpiece without an envelope. The self-mailer usually contains one or more sheets of printed material, folded once or twice by a folding machine into a smaller piece for mailing. Typically, the folded piece has a folded end and an open end (see FIGS. 11-14). The open end is sealed with one or more tabs before the self-mailer is sent to the addressee.
Folding machines are well-known. For example, U.S. Pat. No. 4,701,233 (Beck et al.) discloses a method of folding a sheet by bulging a portion of the sheet and then folding the bulged portion through a roller nip. U.S. Pat. No. 4,875,965 (Marzullo) discloses a folding apparatus wherein a buckle chute is used for stopping a sheet, causing the sheet to enter a roller nip for folding. U.S. Pat. No. 4,944,131 (Gough) also discloses a folding apparatus having a buckle chute. With the above-identified folding machines, when the folded piece exits the folding apparatus, it travels in the direction of the fold. This means that the folded end is leading the open end. Folding machines are generally designed for folding enclosure material to be inserted into envelopes in an envelope inserting device. In this particular application, the traveling direction of the folded piece is not very important. But for tabbing purposes, it is desirable that the folded piece travels with the open end leading the folded end. Thus, while the traveling direction of the folded piece exiting a prior art folding machine is suitable for envelope insertion, it is not suitable for tabbing.
It is advantageous and desirable to provide a method and an apparatus for folding sheets wherein the leading edge of the folded piece exiting the folding apparatus can be selected. Furthermore, it is advantageous and desirable to provide a method and apparatus for folding sheets wherein the length of the sheet to be folded and the type of fold for the folded piece can be easily selected.