A photothermographic imaging material having a support; a photosensitive layer containing photosensitive silver halide particles on one face of the support; and a non-photosensitive layer provided on a side of the support where the photosensitive layer is provided. The ice maker has an ice detecting sensor attached thereto. The grip includes a tubular portion which is mounted to the socket. A third graph is generated by the computing device based, at least in part, upon the analysis of the one or more nodes of the first graph and the one or more nodes of at least the second graph.