Imposition is the process of positioning multiple page images on a single output sheet to be printed at one time. Imposition has no effect on the content of any individual page image; it only affects the size of the page image and where the pages are placed on an output sheet.
Imposition options include the ability to create 2-up to multiple-ups documents including custom multiple-up For a custom multiple-up, the Xerox Nuvera automatically calculates how many images will fit on the sheet size selected for the job. Imposition settings are provided for setting gutter margins and Repeated, Sequential, and Alternating image on sheet outputs.
A Signature is the name given to a single sheet of paper or other substrate after it has been folded. Many books are made up of signatures. The manner in which signatures are bound influences the way that they must be printed.
For more information about setting up impositions, see Setting imposition options.
Saddle stitched books and calendars consist of all the signatures nested in one group with staples inserted at the fold. When signatures are nested, the fold, or gutter, gets wider the further a sheet is from the centerfold (see Figure 1, at the left side).
NOTE: Page frame shifting is done automatically.
Therefore, page frames must be shifted slightly to compensate for the thickness of the gutter. The page frames are moved slightly away from the fold and toward the outside edge. This results in the outside margin becoming narrower. When finished, the sheets closer to the centerfold (with the narrower fold) will have more trimmed from the outside margin. When done properly, the images will appear in the same position on each page as the pages are flipped.
A perfect bound book consists of signatures gathered next to each other, not nested, so that they can be attached together at the bind edge with glue. The groups are in multiples of 4 pages (1 printed output sheet with 2 images on the front and 2 on the back).
The page images are automatically centered within the page frame. The user may request an Image Shift. This will shift the entire page frame on the output sheet. Margins may also be specified; these will reduce the size of a page frame. The system must then reduce the image to fit within the smaller page frame. If Image Shifts are combined with Margins, the image cannot move outside the margin. Therefore, any part of the image that goes outside of the margin will be cropped.
Figure 1: (left) Nested signatures forming a saddle stitched book. (right) Stacked signatures forming a perfect-bound book.
Figure 2: Page order for a simple 4-page book. Input pages are on the left. Output signature sheet is on the right. Numbers in parentheses represent page numbers on back side of the signature sheet.
Figure y: Page order for a calendar signature. Input pages are on the left. Output signature sheet is on the right. Numbers in parentheses represent page numbers on back side of the signature sheet.
Figure z: (Top) Example of a signature layout for a perfect bound book. (Bottom) Example of a signature layout for a saddle stitched book.