Water softening device and washing machine

A washing machine comprising:

• a washing vessel;
• a detergent supply case to mix a detergent with water, and supply a resulting mixture to the washing vessel;
• a hardness component remover in a treated water passage between a water supply source and the detergent supply case, and configured to soften hard water supplied from the water supply source and supply softened water to the detergent supply case, the hardness component remover comprising a resin charging chamber containing an ion-exchange resin;
• a saturated regeneration water generation vessel in which saturated regeneration water with a regenerant dissolved therein at a saturation concentration is to be generated;
• at least one processor;
• and
• memory storing instructions that when executed by the at least one processor, cause the at least one processor to:
• control the washing machine to supply the softened water and the detergent to the washing vessel during a wash cycle;
• control the washing machine to supply the hard water supplied from the water supply source to the washing vessel during a rinse cycle;
• perform a regeneration process to regenerate the ion-exchange resin by supplying the saturated regeneration water to the hardness component remover;
• control the washing machine such that, in the regeneration process, the saturated regeneration water is mixed with water to generate conditioned regeneration water having a regeneration concentration less than the saturation concentration, and the conditioned regeneration water passes through the ion-exchange resin;
• and
• in the regeneration process performed for a first time after the regenerant is replenished in the saturated regeneration water generation vessel, perform water supply increase control such that an amount of water supplied to the saturated regeneration water generation vessel is larger than in the regeneration process performed for a second and subsequent times.