What is causing black streak

clean the slit glass its the small maybe two inch wide glass to the left of the main glass clean it good use windex or alcohol that will get rid of you problem have a great day

This sounds as if you have some ink/contamination on the small scaning glass that sits to either the left or right of the main glass on the copier.(Depending on the model/make)As your original is scanned over this thin piece of glass the scanning device will see any spots and this will result in a black line down the page.Please clean the glass with a soft rag.

well ithink tou are using the ADF to copy something...you will have to clean the scanner glass(not the scan bed but when you lift the ADF cover you will see a scanner glass about inch wide)...it should resove your concern...

lift up your adf and locate the thin piece of glass, about an 1' wide, and clean real good with rag and windex. probably white out or some foreign material on that glass.

hth,
razors

Open the document feeder cover. The scanner glass is dirty or you have a bad scanner block.

The problem is that that there a small piece of glass that the doc feeder use's to scan the orginal. You will have to clean the small glass it's about a half of a inch piece and is normally under the doc feeder unit. It will either be to the right side of the main copy board glass or it is under the doc feed unit where the paper goes down through the feeder. It is mostly some white out on the glass, just clean with a dam cloth with water or windex..... Good Luck

the document feeder of that unit have its own scanner glass. try opening the document feeder and clean the scanner glass with a lint free cloth that is moist with water and also clean the rollers of the document feeder

There is a small strip of glass on the left side directly under the edge of the scanner, About a half an inch wide. It has something on it.
May be very hard to see, use a strong glass cleaner or some alcohol and a regular piece of paper to clean it with.

Good, so u are having probs in ADF. Open the cover, lift the rollers and u can see the scanning glass. Take a lint free cloth and clean it. it will be ok.

Even a single grain of dust or a single strand of hair on the scanning glass will cause the scan head to perceive ink/image where there is none. Deffinetly try cleaning the glass using a good window cleaner, and a cloth that is completely clean, or even a peice of newspaper. If the black line remains, I would suggest taking it into a service center to have the scan head itself cleaned.