A fuel processor for producing a hydrogen-rich product gas suitable for direct use in fuel cell applications includes a housing, an annular shiftmethanator reactor vessel at least one reactor vessel wall disposed within the housing and forming an outer annular space between the at least one reactor vessel wall and the housing. The ring has an external face bearing against an internal face of the rim, thereby resulting in a first axial force, an internal face bearing against an external face of the root, thereby resulting in a second axial force, the axial forces being radially offset relative to each other, and an outer face bearing against an inner face of the base of the flange, thereby resulting in a radial force. The invention additionally relates to an optoelectronic sensor having a metallic sensor housing in accordance with the invention and to a method of manufacturing a metallic sensor housing in accordance with the invention. A series of inkjet printhead modules is mounted on the ink distribution member.