This is a copy of the Instructions HP gives to print on custom Paper.
The conlusion is, HP does not support Custom Papersizes. You must select the largest Paper possible and set the Margins in such a way that a custom Papersize is simulated.
Steps to Print on Custom Paper Sizes
1. Slide the paper-width adjuster to its leftmost position.
2. Pull out the paper-length adjuster and remove any paper from the IN tray.
NOTE: Ensure the card guide is in the down position (used when printing postcards and index cards).
3. Remove up to a .5 inch (1 cm) stack of paper from its package and tap the short edge of the stack on a flat surface to even the stack.
Make certain the width of the paper is between 5.0 and 8.5 inches (127 to 216 mm), and ensure the length of the paper is between 5.83 and 14 inches (148 to 356 mm).
4. Note the width and length dimensions of the nonstandard sized paper. (These measurements are used later on, to determine the correct paper-sized settings for nonstandard-sized paper.)
* Width (X) =
* Length (Y) =
5. Insert the nonstandard-sized paper evenly into the IN tray, print side down, until it stops. Align the right edge of the paper stack with the right side of the IN tray.
6. Align the right edge of the paper stack with the right side of the IN tray.
7. Slide the paper-width adjuster to the right, until it aligns with the left edge of the paper stack.
8. Push the paper-length adjuster in toward the paper until it stops.
NOTE: When the media is shorter in length than 8.66 inches, release the handle of the paper-length adjuster and slide in to the edge of the paper (as indicated above in the Loading Index Cards section).
9. Determine the margins of the document. Record them using the following identifiers:
* Left ( L )=
* Top ( T )=
* Right ( R )=
* Bottom ( B )=
10. In the Page Setup dialog box, select a media size that is larger in both the width (M) and height (N) than the paper in the HP DeskJet 690C Series printer. In the software application, account for the differences by setting the printing margins as follows:
* Left = (L)
* Top = (T)
* Right = (M - X + R)
* Bottom = (N - Y + B)
NOTE: Ensure the paper does not bend in the IN tray.
Copyright (C) Hewlett-Packard Co. 1996 This information is subject to change without notice and is provided "as is" with no warranty. Hewlett-Packard shall not be liable for any direct, indirect, special, incidental or consequential damages in connection with the use of this material.