You're not alone with this problem, I have exactly same problem with a Canon i455 regardless of using genuine or compatible carts. I had to do several deep cleans and take the printhead out and soak in warm water to get the black up and running again. It now works ok as long as it gets a run weekly to keep it free, problems seem to be with lightly used printers as is mine. Have been in touch with Canon, I can and probably will return it to their UK service centre for an examination/service under warranty when I can be bothered. Never any problem with the colour but I have noticed that there is a sponge under where the colour head rests but not under the black head which I suspect allows it to dry out. I think I saw another similar post in the past day or so.