Image: The flush box (1) is located alongside the wiper blade (2) and capping station (3).
Periodically change the flush pad out. The flush box is actually a long rectangle just in front of the wiper blade where the head spits ink to keep all nozzles open. The pad eventually becomes saturated and can leave ink on the head as it passes and will drip on your transfer. The pad can be rinsed out in a pinch but will eventually dry out and no longer do its job. The pad is cheap and it’s easiest to just replace it.
-Kevin Lumberg, Johnson Plastics Plus