Provided is a pagewidth printhead for an inkjet printer. The printhead has a printhead integrated circuit, a molding for supporting the printhead integrated circuit and distributing ink along the printhead integrated circuit, a core element bonded to the molding, and, an outer shell with a first metal layer sandwiched between two second metal layers, so that an effective coefficient of thermal expansion of said shell is substantially equal to that of the printhead integrated circuit. The core element defines ink reservoirs in fluid communication with the molding.