A thermal inkjet cartridge for an organic solvent-based ink includes a cartridge housing, a printhead attached to the housing, and a collapsible ink reservoir disposed in the housing. The ink reservoir has an opening through which ink is supplied to the printhead in fluid communication with the ink reservoir. The reservoir includes a basin member defining a first major portion of the ink reservoir and a movable plate defining a second major portion of the ink reservoir. At least one of the basin member and the movable plate includes a barrier layer for reducing the migration of solvent from the ink reservoir to an external environment.