Darn I was afraid of that and the pictures not coming out at all confirms it is the colour nozzle. The next step would be to try a print head cleaning kit like this one: Click Here
It says Canon but it works with all brands as all kits come with the same thing just in case you ever need to use it with another machine and have some left over. It comes with solution that dissolves dried ink that may be on the sensors or in the ink line a syringe and instructions. If this still does not work it is it means the print head has failed. In order to fix this the print head inside the printer needs to be replaced.
I really hate to have to tell you this but after the troubleshooting we have done if the problem is still there I am sorry to say you indeed are going to require a new part. I know this is not what you want to here but I want to make sure I am honest with the information I provide you. You would need to replace the print head in order to fix this issue.
I wish there was another way but with everything you have posted I am confident this is the problem with your machine. The reason for this is he print head is the part of the printer that puts ink from the cartridges onto the page. Over time these parts deteriorate and need to be replaced.
A new print head normally costs between €55 and €80. It would take about 30 minutes to an hour for a tech to replace it at their shop rate. Most Shops charge between €50 and €55 per hour. I would call around for a price though as some shops will sell a used print head removed from a unit that had a failed main board etc.
Due to the price some people do decide to replace the machine if it is more than a year old if you decide to go that route I would be happy to help you find a replacement.
If this machine is under a year old Canon will normally cover the part under warranty. If you have any questions or need any help following these steps click on reply to expert and let me know. If not please consider leaving a positive rating for my help it is greatly appreciated.