Mimaki TX2 printers:

Clogging within the pump area occurs most likely not in the pump but in the tubing thereafter. Why?

The tubing attached to the pump directing the ink to the waste ink pipe is made out of several pieces so there are obstructions in this tubing and therefore most likely clogging the tube in the area where the tubes are connected. The clogging of the tube will then avoid the air coming into the pump and therefore the pump will not clog that easily.

Note: That reduced performance of the print head occurs even if the clogging is in different locations of the printer just because the pump in both situations can not work properly.