HP DESIGNJET L26500 Series - Substrate Bow Deformation

The framing problem may be solved by printing a sample and adjusting the size of the image in the RIP. You
may reuse this value for all your future prints with the same substrate, although special care must be taken
when using banners, as the shrinkage may vary up to 1% depending on the amount of ink used in the print.
You can expect the following variations from one print to another:
●
Photorealistic, Paper-solvent, Paper-aqueous: less than 0.4%
●
Self-adhesive: less than 0.7%
●
Banner: less than 1%
To solve the tiling problem and improve the repeatability of the printed size, you are recommended to ensure
that the substrate-advance sensor is enabled in the RIP's substrate preset, as this will improve the stability
of the prints over time. You are also recommended to tile together areas with similar amounts of ink. If this is
not possible, print the areas with different amounts of ink as different jobs and modify the length of the job
with less ink in the RIP to match its size with the job with high ink content.
Some RIPs may provide a scaling option that allows you to compensate easily for substrate shrinkage or
expansion; see your RIP documentation.
The substrate has bow deformation
The following substrates may suffer from bow deformation during printing, as a result of which the print will
appear curved.
●
Self-adhesive vinyl substrates (some specific calendared vinyls only)
●
Cellulose-based poster papers with no backing nor coating, including HP Photorealistic
This deformation may be particularly noticeable in the following applications.
●
Printing images that will later be cut automatically or manually. When there is bow deformation, cutters
that are aligned on the sides may lose alignment in the center.
●
Poster printing, if the poster is framed or mounted on a straight surface.
The example below shows an original image, the substrate suffering from bow deformation, and the
resulting print, also suffering from bow deformation.
You can use the straightness optimization option in the front panel, or in your RIP software, to compensate
for this effect and restore the original shape of your image.
At the front panel, select the
icon, then select Image quality maintenance > Straightness optimization,
and select a correction value from –15 to +15.
The chosen value should represent the vertical distance in millimeters that the centre of the substrate has
moved with respect to the left and right edges. If the deformation moves the center of the substrate in the
direction of substrate advance, the correction value should be negative; if in the reverse direction, the
correction value should be positive. In practice, the required correction value is normally negative.
ENWW The substrate has bow deformation 67