You mean patented? I'm sure that the Canon engineers and lawyers could develop a better design that would not violate patents. A straight through paper flow is hardly something that Epson can patent, but I will leave it to the patent lawyers to debate that point.
Thanks for correcting the auto correction
As I remember, the straight through paper flow "IS" patented by the Epson. This information may not be 100% but I got this from the HP management group in China.