Provided is an impression tray which enables impressions of upper and lower jaws to be taken at the same time, and on which an impression material can be heaped sufficiently. An address converter assigns unique names to respective nodes belonging to the private address network and manages the nodes under the unique names. The insert has an outer periphery that conforms to the shape of the groove and has an inner periphery that conforms to the shape of the metal roof seam. After that, recording can be executed in zone 3 next to zone 2. In one embodiment, at least one cut is made through the drainage sheet and the absorption layer, and the hump-forming element is pushed up through these layers. A pixel value of a pixel to be removed is reflected into a pixel value of an adjacent pixel and a reduced image is generated using the reflection result and the removal result.