A sealing structure includes a first substrate having a first compartment, a second compartment and a first base surface. Preferably the laminate pad comprises an inner layer made of vibration damping material such as an elastomeric material and preferably silicone gel. The thickness of the metal film determined based on the detected X-ray fluorescence is compared with a preset value to continue deposition if the determined thickness is less than the preset value. The ink-receptive material includes an ink-receptive coating on a backing layer. The channel cap also may include one or more seals to maintain insufflation pressure both when an endoscopic instrument is inserted in a working channel of the endoscope and when the instrument is not inserted in the channel.