Abstract: A modular ink delivery system using ink jet heads effectively supplies ink to a multi-level array of ink jet heads, and ensures that the heads remain in position during printing even if there is vibration of the supporting structures. Delivery is provided by a number of ink containing chambers, at least one for each level and stacked one atop the other. A connection extends from each chamber to at least one ink jet, and ink is automatically supplied to all of the chambers for example by pumping ink to the upper of the chambers, the ink then cascading downwardly from each upper chamber to a lower chamber through standpipe connections between them. The heads are positively held in place by a first circular bar and a second non-circular bar, which bars are operatively engaged by a mounting block for each head for guided movement.