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Stufenfalz- oder auch Treppenfalz

http://www.druckerei-prinz.de/lexikon_ergebnisse.asp?suche=a...

Images
http://tinyurl.com/ngydsu

Accordion fold
Zigzag type of fold in which a sheet of paper has two or more parallel folds that open in the manner of an accordion, permitting the paper to be extended to its full breadth with a single pull. Travel folders, for example, are often arranged in an accordion fold. Frequently used in the preparation of direct-mail literature, the accordion fold allows the imprinted matter to be divided into more than four contiguous pages. It also saves on both the expense of binding and the bulk of stapling (making a difference in the weight and therefore the cost of mailing). The decision to use an accordion fold for a piece of advertising literature depends in large part upon the advertiser's budget and upon whether the copy lends itself to this format.

http://www.answers.com/topic/accordion-fold

Ich wähle die niedrigste Antwortsicherheit, weil ich die vorherigen Antworten eigentlich nur kombiniere.
Stufenfalz scheint der Oberbegriff zu Treppenfalz (staggered stepped accordion) und Pyramidenfalz (centered stepped accordion) zu sein.
Siehe http://www.foldfactory.com/accordion.php