Horizontal line on printed page

Normally horizontal line [a thin vertical line across the center of the screen] fault with CRT based TVs is the fault with its vertical scan output section circuit. Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If the voltage is absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Type in this key phrase " my service table today " in the search box at the top right of the display window of the home page, to get gathered some pages which has the details of practical experiences to the author of that site.

Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If the voltage is absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/
Type in this key phrase " my service table today " in the search box at the top right of the display window of the home page, to get gathered some pages which has the details of practical experiences to the author of that site.

Is it prints or copies or both? If it's copies, clean the document feeder glass - small strip. What make/model? Laser? If laser, check the fuser roller

Check your flat bed and Document feeder scanning glass need to be clean, if any dot or dust in scanning glass of document feeder it will appear a line, check this points first
1- Check printouts from computer or FAX if it is clean problem in scanning section
2- Check using Copying a blank paper using only Flatbed if it prints without any line its problem from document feeder Scanning glass
So solution is clean the Document feeder scanning glass using wet cloth, note careful about wet cloth switch off the machine and clean it

Documents scanned/copied from the document feeder pass over a thin glass area where scanning occurs. Clean this area if sent faxes, copies or scans have black or white vertical lines.

1. Lift the document cover to expose the platen glass.
   
   
2. Wipe the ADF scan area (C) with a clean, soft, lint-free cloth moistened with water.
   
   
   
   
3. Then wipe with a clean, soft, dry, lint-free cloth making sure there are no residues left, especially on the platen glass.
   
   
4. Close the document cover and make a copy of a text document to confirm the black line has disappeared.

Hardware failure

If line is vertical.

Try scanning a bigger document. Use a blank page big as the scan capacity and scan the blank page.

If for example you are using an a3 scanner, scan a blank A3 page.

When scanning blank page set resolution to an high value, so that you does not lose pixels.

Check scan result, and explore the whole document using zoom to see if the line is still present on the test scan of the blank page.

If there is still the line, then it is either a scanner dirty, probably inside glass, or a dafective sensor on CCD sensor array.

If there is no line, then the problem is usually depending on the software.

In that case uninstall the software and install it again.

If that is not enough to fix the problem, try uninstalling software, doing a system restore to a date before the problem started , and then installing software again.

If the line is horizontal , that is usually a loss of power on the high voltage to lamp.
Try reinstalling software first, if that does not fix the problem , and line is horizontal, then it is fault mentioned above.
Horizontal lines at the end of a document may also be caused by faulty scanner control board, or scanner going out of memory.

Does this happen both when copying and printing?
For printing solution, try another toner cartridge.
If lines continue to appear when copying (primarily through the automatic feeder) then lift the auto feeder, and clean the glass -mainly the narrow piece on the left side.

please rate solution :)

Clean the ADF roller and the far left hand side of the glass, the small strip outside the 'main' panel.

I need to know if this is a sudden occurence or has it happened before. Is cartridge new or refilled or older, and did it print right until now. Also need to know if you have made any recent system changes and if you run anti virus and spyware.