Items returned through the outdoor book drop are identified and checked back in using a mechanical sorting system. You can see the library's sorter through the glass doors on the way to the Children's Library.
The sorter uses belts and rollers to put items in the appropriate bins with others of their type. This means fewer hands have to touch items to get them back on the shelves, and items are available faster.
The sorter is only able to identify and check in items that are flat on the belt and don't overlap. Putting items in one at a time, and waiting for the green light, helps to ensure that items are spaced far enough apart so that they can be sorted.
CPL has had our current sorter for 10 years. The video below is from when it was first installed. In 2022, we plan to replace our sorter with a new model. With advances in technology, this may mean that you'll be able to put in multiple items at once - but until then, please wait for the green light.