Well, now, jannyloubran,
I hope that I understand your question: are you saying that there are vertical bands when an image is scanned, and then printed? In other words, if you download, say, a picture from your digital camera and print it, no bands: but, if you scan a photograph, then print the scanned image, you get the bands?
Going on that assumption, I would guess one of two things is happening, and possibly both:
- The resolution (usually "dpi" in America) is set too low on your scanner to get a very good scan, and so the print is poor. To scan a picture, you really should set the resolution as high as your equipment will allow and your hard drive has space for (the higher the resolution, the more space the file created from the scan takes). Without getting too technical and getting into optical vs. interpolated resolutions, 1200 x 1200 is usually an adequate starting point that will give a decent image (hopefully sans bands) without taking up gigabytes of storage space per scanned photo. You need to open the scanning software that came with your printer and set the resolution higher. If you can't figure out how to do that, open the help file that came with it or go to http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=SupportDetailTabAct&fcategoryid=238&modelid=13800. From here, you can search their FAQ, ask a question from their knowledge base, send tech support an email, or get a phone number for support.
- If your scanner is an older one (you didn't specify), then it may be either worn out (unlikely) or simply not able to support a high-enough resolution for the quality we have come to expect.
Now, if it turns out that I have been having a bad dream and none of the above applies, please repost with more information as to exactly what you have to do to replicate the problem, including what, exactly, you mean by "bands" (black and white bands, bands of fuzzy focus, bands of off colors, wide bands, narrow bands, bands all the way from top to bottom or just halfway, or what?). Also, have you changed anything else between printing from the computer and trying to print the scanned image, such as new cartridges or aligning or cleaning the printhead? I know it's a pain to spell it all out, but sometimes that's the only way we geeks can figure out how to help—and, I hope this helps!