An ink leakage prevention system, for a liquid electrophotographic printer having a development tray, which includes a chassis, installed at a main body of the printer, a development tray, installed at the lower portion of a development unit and is detachable from the main body of the printer, wherein the developing tray accommodates developer left over after being used by the development unit for developing and which has a discharge portion for discharging the accommodated developer, a drain tray installed at the chassis to drain the developer discharged from the development tray into a circulation tank, and a discharge portion opening/shutting means for closing the discharge portion when the development tray is separated from the drain tray and for opening the discharge portion when the development tray is coupled to the drain tray. Thus, when the development tray is replaced or repaired, the parts in the main body of the printer are prevented from being damaged by any developer remaining in the development tray. Further, the present invention provides a simple structure wherein the packing holder which houses the packing member is directly installed in the discharge portion.