Abstract: A container for ink for a writing instrument including a reservoir for containing ink, an ink feed for connection to a writing tip of a writing instrument for conveying ink from the reservoir to the writing tip, and a valve between the reservoir and the ink feed. The valve is subjected on one side to pressure in the ink feed and is subjected on another side to atmospheric pressure. The valve opens when pressure in the ink feed falls sufficiently below the atmospheric pressure acting on the valve, thereby allowing ink to flow from the reservoir to the ink feed.