When I try to print in colour I get yellow lines through everything. The cartridge is new so it's not running out of ink. Do I need to clean the heads somehow? If so, how do I do this?

Try cleaning nozzle with dry paper towel, cartridge should leave 3 streaks: Yellow, Cyan, Magenta.
If colours on paper seams to be tinted or mixed the cartridge needs to be reclamated, there is no other solution.
If there is an lack of one or more colours try to wipe nozzle with wetted paper towel in window cleaner. After few wipes, 3 colours sholud apper

You must set to clean the print head. Yellow ink doesn't work. Try to clean the print head with some hot water, untill you'll see yellow ink came out. Time to time you must print some color files do not dry the ink.

I have personally encountered similar problem in my work. There is no problem with your printer.

Sometimes when either of the inks overflow at the nozzle, it gets absorbed to an extent into another ink compartment. So that colour affected now prints another colour; the colour that has crept into its compartment, Sometimes it is serious at other times is not. If not serious, usually, after a few solid colour prints the colour affected returns to normal.

I do not know how much of a technical person you are, but I will give you the solution to returning your colours from green the right colour. Bring out your colour cartridge. Peel off the seal covering top of the ink cartridge. You will see the holes through which in is fed into it. Get a clean handkerchief, fold it and place over the top of the cartridge. Hold it over a bowl or something. Now place your mouth over the top with the handkerchief in between and blow hard. Ink will discharged at the nozzle. Clean off the ink. (At the nozzle do not rub only dab). Now press a piece of folded tissue to the nozzle firmly. It should be blotted with ink:- red, blue, yellow. If any colour is missing you may need to repeat the procedure. Once you get the three colours back, the issue is resolved.

Sounds like you have cyan and magenta ink but no yellow. (You need yellow to get yellows, greens, reds and orange shades.) First try running the printer utility to clean your ink jets, then run a test print. If this does not work then simply replace the yellow ink cartridge.

A technique to improve print quality is to try and clean the cartridge nozzles. You may clean the cartridge by following the steps given below: 
1. Go to the "Lexmark solution center." This can be done by clicking on "Start," go to "Programs" and Lexmark printer group. Click on the "Lexmark Solution center." Next click on the "Maintenance" Tab.  2. Select "Clean and Fix Horizontal streaks."  Click on "Print". This will produce a printed page. 
The colors that you should see here are black, yellow, magenta (a reddish purple) and cyan (a dark sky blue). You should notice the diagonal lines above and below the solid horizontal lines. These diagonal lines should be solid from left to right with no gaps. 
If there are gaps in the lines or the print diminishes across the page, you should run the "Clean Print Nozzle" page a couple more times to try and clear it up. If you still have gaps at the top and bottom, you should "wick" the cartridges by following the steps given below: 
1. Please open the "Solution center" again and go to the "Maintenance" Tab.  2. Select "Install color/black cartridge" and remove the cartridge or cartridges from the printer.  3. Get a damp paper towel.  4. Set the ink cartridge right side up on the damp paper towel so that the ink nozzles are against the towel and hold the cartridge in this position for about 15 seconds.  5. Now wipe the print head (on the bottom where the ink comes out) across in one direction only (left to right) until it looks clean.  6. Next dab the cartridge on the towel to make sure that the ink is flowing.  7. Snap the cartridges back into the printer.  8. On your computer, select "Old Cartridge install."  9. Repeat the "Clean Nozzle Page" one more time. If this fails to address the problem the entire procedure may need repeating.

If you have run the nozzle cleaning utility, and you are not getting any yellow output, the cartridge is most likely defective. This also occurs if you are not using OEM ink cartridges.

Hi there. The reason for your problem is that the colour cartridge contains cyan, magenta and yellow ink, plus a black cartridge of course. All the other myriad colours are produced by mixing these four basic colours. So, if you print red, it requires ink from both the magenta and yellow cartridges. Thus if your red produces a yellow print, it means your magenta is not printing. This can be due to a number of reasons, mainly an empty or faulty magenta cartridge or blocked magenta print nozzles.

If you wish me to help you with sorting out the lack of magenta, please post a new comment to this effect.

Since the printer cannot detect the amount of ink in the cartridge, the OEM companies place a chip inside of each cartridge that counts the number of pages that you print. When the cartridges reach a certain number of pages, they automatically tell your printer that you are running low on ink, even if it is not empty yet.

If the cleaning steps on your printer is still not fixing the color, try the very first tip on this page:

http://swapink.com/Merchant5/merchant.mvc?Screen=cp_faq&Store_Code=SI

I have found that using warm water on the paper towel clears the prints up better.

this is not a printer problem, you have a problem with colour cartridge! u can fix this in 2 diferent way: 1. replace the colour cartridge with new one, or gently clean the nozzle cartridge with a wet tissue until the cyan colour mark a line on the tissue just like the others colours: yellow and magenta. maybe must repeat this several times.

Yes, do you refil your own inks. Colour contamination occurs primarily when users overfill ink holes with any colour, then this colour runs into others and voila, a yukky mess. If cartridges are fairly new, heres the quick easy fix. Remove cartridges that are causing the problem, in your case all! Using a proper cleaning solution (you can get this free in refill kits or buy it sepeartely, i got mine from supermarket, works well) and cotton buds, thoroughly clean down where the cartridges sit. There will be both fresh ink and dried ink, so you will have to repeat over and over until all or most colour is gone from cotton buds. Now, let it dry and air, leaving printer cover open. You now have to bleed the black ink as it sounds like it is overfull. This can happen in refilled cartridges, but even store bought ones can have faults. Sit the black cartridge on wet paper towel, on a clean icecream lid or marg lid, even a plate will do, just one that you don't mind ink on by accident. Let it sit a minute or so, now lift it up, and wipe it gently with a wipe (i use unscented baby wipes-huggies, do not laugh, they work well!) press it firmly on a folded tissue, and it should leave a nice clean neat black vertical little line. If it doeas, place it back in its place in printer. Leave open for now. The colour cartridge should need cleaning too, by doing the same, each time you lift it off wet paper towel, wipe it clean, and press it on a tissue to see clean neat 3 colour line. If not, bleed again until it does. When it does place it back in printer and reset ink levels once cover is shut. Try printing now.