A device for environment detection having a first magnetic alternating field is situated in a vehicle. Following the French press process of brewing, a filtration piston is inserted into the brewing chamber. Unlike the conventional foam materials presently being used by the footwear industry, a preferred spring element is not substantially subject to compression set degradation and can provide a relatively long service life. The test pattern images printed as above are used to visually observe and determine a degree of error in the amount transferred by the respective rollers. A light diffusing sheet andor colored sheet for a screen are also disclosed. The portable thermal printer comprises: a housing provided with a thermal printer head; a cover openably attached to an opening portion of the housing by a pivotal shaft, the cover being provided with a platen roller arranged to make contact with the thermal printer head when the opening portion of the housing is closed by the cover; and a drive power source provided within the housing.