Compositions containing a peroxide or peracid and an organic acid salt buffer are provided. The terminal preferably has the shape of a well seat closed at one end by the display, thereby enabling a large number of users to distribute the space around the display. After insertion thereof through the sensor mounting groove such that side surfaces of the narrow portion are made parallel with the sensor mounting groove, the holder is turned, whereby the widened portion engages within and is retained respectively by a pair of recess portions in the sensor mounting groove. The belt member is brought into contact with the first roller to form a nip portion therebetween through which the recording medium is passed.