Imagine you have a big coloring book with lots of pictures. To color them all, you have to flip through the book, find the right page, and carefully color inside the lines. This takes a long time and can be tiring.
Now imagine you could flip the pages really quickly without having to use your hands. That's what a rotary printing press does! Instead of flipping pages by hand like you do with a coloring book, a rotary press uses a big spinning wheel to move paper through the machine.
As the paper moves, large metal plates with raised images on them press ink onto the paper. These plates can have lots of different colors or even pictures on them. The ink sticks to the raised parts of the plates and gets transferred onto the paper in that shape. This means you can print lots of different pictures or words on the paper as it goes through the press.
All of this happens super quickly, so you can print lots of pages in a short amount of time. In fact, rotary printing presses are often used to make big newspapers or magazines, which need to be printed and distributed every day.
So, a rotary printing press is like a super-fast coloring machine that can print lots of pages really quickly!