Scanning empty pages with scanimage

Hi all

I recently got a new HP 5510 All in one printer scanner.

I run SUSE Linux 9.2 and a can print an scan o.k. with one exception.

When I try to scan a single page via ADF using scanimage everything is
fine
(scanimage --format tiff --mode Lineart --resolution 300dpi  >
scan1.tiff)

If I try to scan mulitple pages I get the correct number of images files
- but all the images are empty
(scanimage --format tiff --mode Lineart --resolution 300dpi
--batch-scan=yes -b)

I changed the orientation of the pages, upside down etc. but no
difference.

any help would be appriciated.

regards
stefan