Methods, articles of manufacture, and apparatus to count people in an image are disclosed. A vertical rail system is configured to slidingly engage a bracket of the window sash. The second print device calculates, based on a web transport speed at the generation timing of the CPF-OFF signal, a time duration required for the web to reach a predetermined waiting position after the CPF-OFF signal was generated, and starts counting a clock when the time duration elapses from when the CPF-OFF signal was generated.