I have a CanoScan Lide 20 which is just on two years old. It has performed well up until now. I need to scan black and white documents as PDF's (mainly to email) My scans are now quite "patchy" and with the odd line through the text. I have cleaned the glass and can see no obvious problem. Have tried different settings for saving to file, and also tried copying to two different printers with no difference. Is there anything else I should be looking for....apart from a new scanner? Are the Canon scanners usually reliable for more than two years? I already have an obsolete Umax after changing to XP several years ago. Thanks for any information. Regards Kaz