An electrostatic printing machine having a plurality of color stations having a system for maintaining a preset toner age in each of the plurality of color stations, including: determining a toner age for each of the plurality of color stations; determining if purge while run is required based on the toner age for each of the plurality of color stations; defining an area on a unused portion of an imaging frame for a purge patch, the defining includes sizing a plurality of purge patch regions wherein each of the purge patch regions may have a different size; allocating each of the plurality of purge patch regions to at least one color plane from a group of color separations.