A printhead assembly arranged to impede printhead module nozzles from drying out. The printhead assembly comprises a plurality of the printhead modules arranged along an axis. Capping devices are provided to cap respective printhead modules. A positioning arrangement is also provided for positioning the capping devices relative to the printhead modules so that the capping can be moved between a printing position and a capped position. In the capped position, nozzles of the printhead modules are capped so as to impede the nozzles from drying out.