Thermal printing apparatus and printing methods thereof are disclosed. A photoelectric conversion device includes a photoelectric conversion element for outputting photocurrent corresponding to illuminance, and a resistor changing resistance corresponding to illuminance. A lock down ring 34 may limit axially upward movement of the hanger with respect to the wellhead, while a support ring 32 may be used to limit axially downward movement of the hanger with respect to the wellhead housing. A presentation of the extracted content may be displayed on a display screen while excluding a reset of the document without displaying the web page.