An integrated circuit package is proposed in which a laminar substrate 41 is provided with an aperture 43. The sensor has, for example, a substrate, a recessed channel formed in the substrate, and conductive material disposed in the recessed channel to form a working electrode. The apparatus is configured such that a wedge-shaped space, which is formed between a belt, a separation roller, and a pressure pad, is adequately filled by a sliding sheet, thereby preventing a pressure in the fixing nip from being decreased.