Provided is a maintenance fluid excellent in terms of
humectant property and cleaning property. The maintenance fluid is for use in ink-jet recording devices, and comprises organic solvents that comprise a
lactone-based
solvent and an
organic solvent A, wherein the
organic solvent A has a
boiling point of 240-310°C. The maintenance fluid has a volatile content X, as determined by the following test, of 900 g / L or less. Testing method: In accordance with the provisions of GB / T13173-2008, Chapter 15, the volatile content X is determined using equation (A) . VolatilecontentX=Wv×p×0.01 (In equation (A), Wv is the
mass fraction (unit,
mass%) of the organic solvents contained in the maintenance fluid and p indicates the
specific gravity (unit, g / L) of the maintenance fluid. A two-
gram portion of the maintenance fluid is precisely weighed out and put on a dish having a
diameter of 5 cm and a height of 1 cm. This dish is put in an oven heated to 105°C to dry the maintenance fluid for four hours. Thereafter, the dish is allowed to cool for 30 minutes in a
desiccator and then precisely weighted, and the amount Wv (
mass%) of volatilized components of the organic solvents is calculated.)