Abstract: A pressure fluctuation buffering mechanism includes a buffer space connected to a brush via a paint flow space (a paint tank and a paint feeder) through which paint flows. The pressure fluctuation buffering mechanism buffers pressure fluctuations in the paint tank by the flow of paint and air between the paint flow space and the buffer space. The pressure fluctuation buffering mechanism includes a first buffer space forming member for forming a first buffer space in the buffer space, and a second buffer space forming member for forming a second buffer space in the buffer space. The paint between the first buffer space and the paint flow space flows more easily than the paint between the second buffer space and the paint flow space.

Abstract: A writing instrument 2 includes a pen tip mechanism 20, an ink tank 40, an ink induction mechanism 50, and a regulator mechanism 60. The ink tank 40 includes first and second ink tanks 40A and 40B. The pen tip mechanism 20 includes first and second pen tips 20A and 20B. The ink induction mechanism 50 includes first and second induction cores 50A and 50B. A regulator flow path set around the first induction core 50A and the second induction core 50B is partitioned into first and second regulator flow paths by the regulator mechanism 60. The first and second regulator flow paths are temporary accommodation spaces of inks and circulation spaces for sending air from the induction cores 50A and 50B to the ink tanks 40A and 40B.