Dielectric heating device and printing system
A dielectric heating device includes: an electrode unit including a first electrode and a second electrode that face a to-be-heated object, and configured to heat the to-be-heated object; a voltage application unit configured to apply an alternating-current voltage to the first electrode and the second electrode; a current value detection unit configured to detect a current value of an alternating current that flows through the electrode unit; a phase difference detection unit configured to detect a phase difference between the alternating-current voltage and the alternating current; an impedance detection unit configured to detect an impedance of the electrode unit based on the current value and the phase difference; and a control unit configured to control output of alternating-current power output to the electrode unit by controlling the voltage application unit based on the impedance.
1. A dielectric heating device comprising:
an electrode unit including a first electrode and a second electrode that face a to-be-heated object, and configured to heat the to-be-heated object;
a voltage application unit configured to apply an alternating-current voltage to the first electrode and the second electrode;
a current value detection unit configured to detect a current value of an alternating current that flows through the electrode unit;
a phase difference detection unit configured to detect a phase difference between the alternating-current voltage and the alternating current;
an impedance detection unit configured to detect an impedance of the electrode unit based on the current value and the phase difference; and
a control unit configured to control output of alternating-current power output to the electrode unit by controlling the voltage application unit based on the impedance, wherein
the electrode unit includes a coil electrically coupled in series to either one of the first electrode and the second electrode.
2. The dielectric heating device according to claim 1 , further comprising:
a storage unit, wherein
the control unit estimates a dryness degree of the to-be-heated object based on the impedance, and causes the storage unit to store the estimated dryness degree.
3. The dielectric heating device according to claim 2 , wherein
the control unit estimates the dryness degree by estimating an amount of a liquid contained in the to-be-heated object based on the impedance.
4. The dielectric heating device according to claim 2 , wherein
when the dryness degree is equal to or higher than a predetermined degree, the control unit sets the output of the alternating-current power to 0.
5. The dielectric heating device according to claim 1 , wherein
the control unit estimates a temperature of the to-be-heated object based on the impedance.
6. The dielectric heating device according to claim 1 , wherein
the voltage application unit includes an inverter configured to convert a direct-current voltage received from a direct-current power supply into the alternating-current voltage to output the alternating-current voltage to the electrode unit.
7. The dielectric heating device according to claim 6 , wherein
the control unit controls the output of the alternating-current power by causing the inverter to intermittently operate based on the impedance.
8. A printing system comprising:
the dielectric heating device according to claim 1 ; and
a discharging unit configured to discharge a liquid to a printing medium and to cause the liquid to adhere to the printing medium, wherein
the electrode unit heats the printing medium to which the liquid adheres as the to-be-heated object.