Hello, I'm Wes, and I'll be assisting you today.
The print quality is set from the computer.
When you are ready to print, click the Print button on your software.
Then the print dialog box will display.
In the properties window you can set the quality option
The quality option you may want to try is Photo or Best Photo
Let me know if you need additional help so I can assist further.
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There are two possible causes.
1. The scanner glass is dirty and needs to be cleaned. You can clean the glass to see if this helps.
2. The scanner optical sensor has gone bad and needs to be repalced. This will require either warranty replacement or a printer service technician.
Place a photo on the scanner tray and use the copy button to test the printer itself.
This will eliminate the computer and see if the issue is with the printer or computer.
Ok. Then it is the computer that has the quality issue.
Let's reinstall the latest drivers for your printer.
Download and install the latest drivers using this link:
That is the strange thing.
It's definitely the computer. If the driver doesn't help, I would suggest taking the computer back as you mentioned.
Here is a link to download My Image Garden
Using the same link, download and install the first option (Full Software) and it will include the Canon Scan Utility.