There is provided a pigment dispersion comprising at least one resin-coated pigment comprising a resin and a pigment, and having an average particle diameter of 250 nm or less, and a dispersion medium containing as a major component a cation polymeric compound having a viscosity of 30 mPa\xb7s or less at a temperature of 25\xb0 C. The stationary unit includes a stator, a PCB and a base member. In some embodiments of the present invention, a check valve is provided with the actuator rod that is adapted to prevent the flow of fluid in at least one direction. The CPU resource allocation policy specifies how resources are allocated to the defined workload.