Blue lines from scanner

[MFP227]

After a year of working fine, now all scans from document feeder have parallel blue lines down the length of the pages being scanned.  Only with document feeder, no issues with print, unless printing the scan.  The glass is clean, the rollers inside are clean.  The problem is presumably inside the document feeder or in the long thin glass (covered with plastic) at left under the document feeder which warns not to clean it.  It does not look dirty.  

[Valsimot]

What about copying the original from the feeder and from glass?

[MFP227]

Thank you.  That works fine when only a page, but for multiple page documents not practical and must use feeder.  

[Valsimot]

Open top cover to access glass scanner. On the left side, you have a smaller glass that is used when scanning from the feeder. Clean that smaller glass, it is dirty and dirt leaves lines.

[MFP227]

The smaller glass is covered by a flexible mylar strip that appears to have a tiny imperfection in it.  I have tried to clean and gently scrape it clean but not able to.  I assume it must be replaced.  Is this something than can be replaced, or is the only solution to replace the device?