The printed pages have pink blotches on the right hand side of the paper and horizontal pink blotches down the page

Needs Drum If you pull the drum unit out you will see on the drum different shades of color lighter is wear the lines come from. Buy a rebuilt drum much cheaper and they work, may have to reset the drum count if the change drum lite on...

Click

1. <Page Layout>
2. <Margins>
3. <Custom>
4. Then click the "center Horizontally" box

Run a half test.
Put paper in the manual feed tray.
Print something, anything
When the paper is 1/2 way into the printer, open the cover.
Pull out the toner cartridge. Look down at the paper.
Does it have a black line on the right side?
If yes, replace the cartridge. If no, replace the fuser.

after reading the manual, http://www.lexmark.com/publications/pdfs/2007/2400/ug_en.pdf, yes it is possible - not that it tells you how to do it though so read on.
Until you become familiar with the process just use one sheet of paper at a time in the printer.
As you know, in the scanner the top right of your document goes to the right hand front corner of the scan bed (the clear window), place the page on the scanner and scan.
Pick up the printed sheet of paper and flip it so the left hand side edge is now in your right hand and the right hand edge is now in your left hand and you are now looking at the blank side of the paper.
Insert the page back into the sheetfeeder.
Flip the page to copy in the scanner so the rearmost edge of the paper is now to the front of the scan bed and the front edge of the paper is now towards the rear (you should now be looking at the page you scanned previously).
Scan the page.
you should have now scanned both sides of one sheet of paper to another sheet of paper.
as your printer does not have a sheet feeder for the scanner you have to do the process manually. hope this helps.

If the line has a 1/8" white margin on either side, clean your glass and mirrors.

If the line is all the way across your page, consult your users manual for cleaning the sawtooth electrode (open the front door and take out your waste tank, there is a green rod on each drum cartridge you can pull and hear a zipping noise) and cleaning the laser lens (there should be a cleaning wand under your waste tank, turn pad side down and insert in the gap underneath your drum cartridge)

The scanning bar has 28 leds on it and on my 4100 the 6 leds on the right side were flashing on and off,it could be abad connection on that part of the scanning bar caused by a jamed paper.
to tell if your machine is a printing problem or a scanning problem print out the help menu {press the reports key then the 1 key} if it prints clear then every thing with the print cartrige is ok and the problem is in the scanning part of the machine.

sounds like a soft ware fault , if you have the disc that came with it, you could try a clean install, this will fix any soft ware fault.

Your machine has the wrong paper in it or the paper sensor is not working properly.  There should be a black mark on the top left hand corner of each page.  The correct ekg paper and ekg repair is available from Medical Device Depot.

Either your magenta cartridge is leaking out of the right corner or you have a defective magenta drum.
(maybe it got scratched when changing the cartridge?) If it's the magenta drum, you have to replace all the drums since they come in one unit. OEM part only.

CLEAN THE DRUM (OPC) WITH ISOPROPILE.