K-On! originally debuted as a manga, and it then went on to spawn an anime, a feature film and a video game. It's a pretty popular series, so when it's copied, people tend to notice!
The latest issue of Jump Next features up and coming manga. New comic "Ooedo Punk", which did get some good reviews online, sports some K-On! style eyes and facial expressions that match up with a still from K-On!.
This might be an all out copy, or it might be subconscious. Whatever it is, don't say "lazy".
Update: Eagle-eyed readers have pointed out that the inspiration seems to be Hyouka, which was done by the studio that did the K-On! anime.
【画像あり】 ジャンプに「けいおん」のパクリｗｗｗｗｗ [ラッビト速報]