ADF retains paper

Hello, first of all sorry for my bad english...

I own a hp officejet 6110 all-in-one installed on an opensuse 11.4 box (default packages), but my problem was the same with the previous 11.3 (updated packages via official repositories).

Here the problem:

When i try to scan multipage documents via adf, scan stops with paper jam after the first page. Then i try to scan one page at a time

- insert page in adf tray -> scanner react and recognizes a paper was inserted;
- launch scan program for acquiring image (no matter if i use scanimage or sane), eg. the following command:

scanimage -d hpaio:/usb/OfficeJet_6100_Series?serial=MY38AG732Q2R --resolution 150 --format tiff --mode Lineart -b --batch=out%03d.tif --batch-scan=yes -x 210 -y 297

- scanner head moves to the adf scan area;
- paper start to move into the adf;
- during the scan, half paper progressively moves out from adf;
- paper stops moving and scanner head returns to his home position;
- paper starts to be ejected from adf, and after - i think - a too short timeout ...
- adf movement reverses and paper falls into adf
- i need to pull hard paper to release it (in this case no paper jam error)

Why the adf movement is always reverserd after the scan action? Sometimes paper is correctly ejected becouse this "timeout" is sufficiently long to allow complete paper ejection, but mostly, paper is sucked back about at half his lenght.

Thanks and regards