I am having the same problem. There seems to be a great deal of misinformation on this subject.
It can't scan...
According to this hp forum thread, many older HP OfficeJet multifuction printers only support printing.
http://h30434.www3.hp.com/t5/Scanning-Faxing-and-Copying/mac-10-6-officejet-6110 -can-t-scan/td-p/904761
Their source is the Apple OS/X 10.6, 10.7 printer support KB article, http://support.apple.com/kb/HT3669. In the case of the HPOfficeJet6110 multifuction printer, this Apple's KB article shows "P" (print support) but not "S" (Scan) or "F" (Fax).
It can scan...
HP's support article, http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01664444&lc=en&cc=emea_afri ca&dlc=en&product=79477#N1146 indicates that it should work.
<Quote>
Full print, scan, and fax drivers for HP Inkjet All-in-Ones (Deskjet, Officejet, and Photosmart) are supported by the HP software available from Apple Software Updates. Scanning is supported with the Apple Preview and Image Capture Applications in Lion.
Print drivers for the following product types are supported in Lion by the HP software available from Apple Software Updates. These drivers provide print-only functionality.
- HP Inkjet single-function products (Deskjet, Officejet, and Photosmart)
- HP LaserJet color single-function, All-in-One, and MFP products
- HP LaserJet monochrome single-function, All-in-One, and MFP products
- HP Designjet products
</Quote>
Since this is not a single-function inkjet or a multifunction laserjet, it seems clear that HP is saying that it *does* support scanning.
In summary:
I swear that I was able to scan documents with my 6110 under OS/X 10.6 but I cannot get 10.7 to recognize that the device is a scanner (it only recognizes the printer capability).
I would love to get a definitive answer (and only 1), but I'm afraid the best advice is switch devices (which is a really poor answer, especially considering all I am trying to do is re-use existing hardware -- the scanner would be a convenience for me).
If anyone does get this type of setup working, please post!