Thanks tbiredvet
This is what I found on HP website
I installed it and and its works ! ;-)
OSX 10.10 Drivers for HP Scanjet N6310
http://h20564.www2.hp.com/hpsc/swd/public/readIndex?sp4ts.oid=3723538&swLangOid= 8&swEnvOid=4182
Here are the instructions for setting up the scanner.
1. Enter the model number into Google Search
2. Select hpdriver.com>Scanner Drivers
3. Choose last driver for Mac ICA
4. Choose Language
5. Click on “Drivers & Downloads”
6. Enter “N6310” in “Find my product” Click “Go"
7. Click on “HP Scant N6310 Document Flatbed Scanner”
8. Page expands and repeats previous line. Click on the link.
9. Select “Driver Language” in first box with arrow, and “Select your product’s operating system” in second box with arrow.
10. Window changes to “Mac OS X 10.10 Downloads” Click on “+” in front of “Software 1”. Dropdown opens to display the “Description” “Current Version” Size” “Previous Version” and “Download”.
11. Open download and click on Installer. Follow the instructions.