Abstract: A monitoring apparatus is provided which can ensure the prevention of a paper break even in a poor installation environment. A light source (9) illuminates light (9a) on a lateral edge (1a) of wet paper (1) and a camera (5) captures light (9b) reflected therefrom. The camera (5) is a micro camera and completely covered by a camera box (10). The camera box (10) has an observation window (10a) which is made of a transparent member, at the lens side (5a) of the camera (5). The outer surface of the observation window (10a) is coated and an air curtain (12a) that flows from above to below prevents staining caused by mist. The air curtain (12a) is formed in such a manner that air that is continuously supplied inside a cover (11) flows along the outer surface of the observation window (10a) from an opening portion (11a).

Abstract: There is provided a monitoring apparatus for preventing paper breakage. For this monitoring apparatus, a light source 9 is disposed on the upper side of a wet paper 1, and a light emitting face thereof faces downward. An operation-side camera 5a and a drive-side camera 5b are disposed on the side opposite to the light source 9 with respect to the wet paper 1, and a lens face thereof faces upward. Light 9a of the light source 9 passes through the wet paper 1 after being reflected from a mirror 11, and is caught by the cameras 5a and 5b. Thus, the cameras 5a and 5b photograph a silhouette (image) of the light 9a of the light source 9, which has passed through the wet paper 1. This image is sent to an image processing unit 6, where the image is processed. The coordinates of a boundary line such that the wet paper 1 separates from a center roll 2 is detected from the images photographed from two directions. This coordinate value is sent to a computer 8.