What are these lines of colour on my Epson Perfection V370 scans?

This looks like a calibration issue. Since the pixels on the sensor do not all have the same sensitivity, the scanner should auto-calibrate every time it is powered on. I'm not entirely sure how it does this and the documentation doesn't give any indication. It may scan a test strip internal to the scanner or it may scan the white document mat.

However, your document table (glass) appears to be dirty and this may be the cause of your problem. Another possibility is dirt on the sensor or on the calibration strip (if this is internal to the scanner). Before you try anything else, I would recommend that you do the following:

1. Power off the scanner.
2. Clean the document table and mat in accordance with the manufacturer's instructions. Make sure that they are spotlessly clean but take care not to scratch them.
3. Insert the document mat and power on the scanner with the lid closed and no document inserted.
4. Perform some test scans to see if the problem is resolved.

Always switch the scanner off when you have finished using it.

I had this problem with my EPSON V370. It was first noticed when a colored line appeared on scanned slides. Cleaning the glass screen of dust particles solved the problem.

I have an Canon 9000f mkII and the solution was to clean one if the 3 internal mirrors that has the scan module carriage, mirrors that are wide as a A4 and 1cm high, and take the image from the glass surface to the lens and optical sensor st the end. Please , be careful, use only special tisue with crear care, only breath to humidify something ... And blow airvto tske any particle that the tisue could lay. Clean the plate big glass from the scanner below also justo in case it's dirty. Good luck

I just had the same problem on my Epson Perfection V370. I tried to clean the glass again and again and it did not help at all. I solved the problem only after opening the scanner and cleaning the glass from the inside.