When i turned on the lamp start to move a little bit, then returns and it repeats this until i turn off after a few hours leaving it off (some times until next time) i turn it on and works fine. it print or copy a few pages and then it returns to move the lamp a little and returns

SOURCE: xerox xd100

There are a few things to try. If you have been using the device, I'm certain the first one is not it, but power off the machine. Look on the left side in the middle near the top. If there is a silver screw in the device, that needs to be removed. It is the shipping screw to hold the scanner in place when you are moving the device. Next, check your power source. Power off the device and plug it directly into the wall outlet, not into a power strip. The wall outlet needs to be grounded as well. Still have the code? Try the following (this is from the xerox.com support website)
Performing a Fault Reset 1 01 will reset your Scanner, and allow you to check the Scanner for broken parts as it moves.

1. Find the pink Clear button on the Control Panel of the WorkCentre.
2. Find the button below the word Auto.
3. Press these buttons in the following sequence: [Clear], [Auto], [Clear], [Auto] NOTE: All of the lights on the Control Panel should go out and the LED Display should go blank. If the lights do not go out, then repeat step 3 until they do. It may be necessary to increase or decrease the pace of the [Clear], [Auto], [Clear], [Auto] sequence.
   
4. Press the [1's] Key to enter 1 in the LED Display, as if you were to make 1 copy.
5. Press the green [Start] button. '00' will flash in the LED Display.
6. Press the [1's] Key to enter 01 in the LED Display, as if you were to make 1 copy.
7. Press the green [Start] button. '01' will be in the LED Display and '100%' will be selected.
8. Lift the Document Cover.
9. Press the green [Start] button. The Scanner Bar should move from left to right under the Platen Glass.
10. Visually check the Scanner Bar as it is moving to make sure it runs all the way across.
11. Check the Mirror that follows the Scanner Bar to see if it is broken or cracked. NOTE: If you need to see the Scanner Bar and Mirror move again, press the green [Start] button again.
    
12. Press the pink [Clear] button four times.
13. The WorkCentre should now warm up and come to ready.

SOURCE: Printer is not printing at all, just blank pages

I can help you troubleshoot your printer. Just be prepared if your printer never prints again. This is rare to say the least. I just want you to know that in advance. OK? Laser printers use a static charge applied to the paper to represent your document and then this charged paper passes over the toner and finally the toner on the paper passes under a tungsten wire heated up high enough to melt the toner into the paper. This is why newly printer pages are warm to the touch. So, with three systems doing the magic any one of them can fail due to fatigue.

To start with, when was the last time you changed the toner cartridge?

How old is your printer and how many pages per month has it printed so far, on an average?

Are you under warranty any longer?

Thanks.

Worldvet

SOURCE: system fault

too many black copies, keep black copies down to 400 at a time and break it up with colour jobs

SOURCE: Xerox 8500 - overprinting when double-sided

That normally is caused by a dirty maintenance kit. Often times they dry out and do not put enough lubricant on the drum, I would start with a new mainteanace lit., you may also have a bad wiper blade, although thats less likely.

SOURCE: Xerox WorkCentre 4150, 3 vertical white lines in all feeder scans

the problem is in the scanner, open it up and see if you can find any smudges, and clean any obstruction, any ink, liquid eraser residuals, can cause this part to appear as lines on your copied faxed image.
dont concentrate on the printer this is a scanner problem