Washing machine with drying function

A washing machine with drying function, comprising:

• a cabinet having a laundry insertion hole at a front surface of the cabinet;
• a tub inside the cabinet and having a front opening and a back opening;
• a drum rotatably disposed inside the tub, wherein the laundry insertion hole, the front opening, and the drum are positioned so that laundry is insertable through the laundry insertion hole and then through the front opening to be received in the drum;
• a heated air supplying device including:
• a heat exchange part above the tub,
• a front duct,
• a back duct, and
• a blower fan to form an airflow that flows, via the back duct and the front duct, from the back opening to the heat exchange part, and then to the front opening;
• a lint filter inside the back duct, and configured to filter lint in the airflow flowing through the back duct;
• a sensor fixed to the lint filter and configured to detect lint in the lint filter, and to produce a corresponding signal;
• a washing device configured to selectively spray washing water toward the lint filter;
• and
• a processor configured to control the washing device to spray the washing water toward the lint filter based on the signal produced by the sensor.