An externally mounted mechanical device for mechanically closing a pressurized tank or cylinder valve, such as a grill tank, is provided. A connection terminal group for common electrode 6 is juxtaposed to the connection terminal group for segment electrode 8 along the lower side portion of the sealing resin 7. The rigid retainer and flexible retainer are coupled to the holding frame assembly to define filter retaining pockets that retain a final filter within the holding frame assembly without use of clips and other fastening mechanisms. The control determines the selected temperature for cooking to be maintained in the oven cell by averaging selected temperatures sensed by the plurality of temperature sensors in predetermined proportions based on the selected mode of cooking operation. Thereafter, a conformal cap layer is formed over the insulation layer. If it is determined that an illegible part is present, the thickness of the handwriting character is automatically selected again to be thinner and the image of the handwriting character is drawn again, which avoids illegible part occurring in the handwriting character without inputting the character all over again.