You may want to check your data cable or get a surge protector that has a USB or Ethernet connector in case it's the wattage issue.
I had a customer with the exact same problem on their Pro series from Thanksgiving and Canon tried to get it resolved. The customer had a friend in the military that he spoke to after all of the attempts with Canon and said to try a surge protector with the data cable connected to it and it basically resolved the issue. Seems like a power consumption problem that the cable is trying to work with doing directly to the printer from computer and isn't able to transfer it easily. Weird issue since I never heard of this, but seemed to work for my customer. Hopefully it's not a data cable issue otherwise.
Also, they did have this same exact problem where most of the image would print and had the lined section showing as well. We were dealing with this problem for a few month until he got the suggestion recently for a surge protector with the appropriate connections.