An ink supply unit is provided for supplying ink to a printhead in a printer. An elongate manifold defines a plurality of sets of ink passages and further defines a recess in which the printhead can be received so that the ink passages are in fluid communication with respective ink inlets of the printhead. An ink supply includes an elongate housing encasing a partitioning unit to define a plurality of ink chambers which can each contain a respective type of ink. The ink supply is engageable with the manifold so that ink from the ink chambers can be provided to respective sets of ink passages.