Types of Gravure Folders
The U.S. population of gravure presses has undergone substantial expansion and rebuilding in recent years. Nonetheless, there are still many different folder configurations in use. The following section describes the types of folders used in the industry, and how the folding is processed in the upper and lower folder sections.
• Former Board Newspaper Folder. One fold is produced over a former running in the web direction. The lower folder cuts off the signatures and generally produces a second cross fold. The number of ribbons over the former varies with product size. This folder requires columns around the cylinder page layout (head or foot lead-edge) when producing a full size (broadsheet) product.
• Single Jaw Folder. The upper folder cuts the web into ribbons. One fold is produced in the lower folder after the signatures are cut off at a right angle to the direction of web travel. The printing cylinder page layout requires columns across the cylinder (low or high lead edge).
• Former Jaw Folder. The upper folder produces one fold over a former board. The lower folder produces a second fold at right angles. The signature produced has two sides open. The ribbon over the former can be slit on the center of the former to produce a three-side open signature.
• Jaw Double Parallel Folder. The upper folder slits the web into ribbons. The lower folder produces two folds, both at right angles to running direction of the ribbons, with the second fold occurring after the product is fully folded across its center.
• Former Jaw Double Parallel Folder. The upper folder produces one fold over a former board. Ribbons can be slit on the former center line. The lower folder produces two folds, both at right angles to the running direction of the web travel, as in the preceding example.
• Jaw Chopper Folder. The upper folder slits the web into ribbons. The lower folder produces one fold at right angles to the web dirction, and second fold in the dirction of web travel.
• Former Jaw Chopper Folder. The upper folder produces one former fold. The lower folder produces one fold at right angles to the direction, and a third fold in the running direction of the web.
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