Liquid discharge head cleaning method and liquid discharge apparatus

A method of cleaning a liquid discharge head that includes a heat generating resistor that generates thermal energy for discharging a liquid and a covering portion covering the heat generating resistor, the method comprising:

• performing a voltage reversal application operation multiple times,
• wherein the voltage reversal application operation includes a first voltage application process and a second voltage application process,
• wherein the first voltage application process includes applying voltage between the covering portion and an electrode through the liquid to dissolve the covering portion in the liquid, and
• wherein the second voltage application process includes reversing relative polarities of the covering portion and the electrode in the first voltage application process after the first voltage application process and applying voltage between the covering portion and the electrode such that energy applied is substantially equal to that in the first voltage application process;
• and
• reducing energy applied in at least one voltage reversal application operation such that the energy applied is less than energy applied in an immediately preceding voltage reversal application operation.

A liquid discharge apparatus comprising:

• a liquid discharge head that includes a heat generating resistor that generates thermal energy for discharging a liquid and a covering portion covering the heat generating resistor,
• wherein the liquid discharge apparatus is configured to alternately perform a first voltage application process and a second voltage application process multiple times,
• wherein the first voltage application process includes applying voltage between the covering portion and an electrode through the liquid to dissolve the covering portion in the liquid, and
• wherein the second voltage application process includes reversing relative polarities of the covering portion and the electrode in the first voltage application process and applying voltage between the covering portion and the electrode, and
• wherein the liquid discharge apparatus is configured to reduce energy applied in the second voltage application process at least one time such that the energy applied is less than energy applied in the first voltage application process of an immediately preceding time.

A liquid discharge apparatus comprising:

• a liquid discharge head that includes a heat generating resistor that generates thermal energy for discharging a liquid and a covering portion covering the heat generating resistor,
• wherein the liquid discharge apparatus is configured to perform a voltage reversal application operation multiple times,
• wherein the voltage reversal application operation includes a first voltage application process and a second voltage application process,
• wherein the first voltage application process includes applying voltage between the covering portion and an electrode through the liquid to dissolve the covering portion in the liquid, and
• wherein the second voltage application process includes reversing relative polarities of the covering portion and the electrode in the first voltage application process after the first voltage application process and applying voltage between the covering portion and the electrode such that energy applied is substantially equal to that in the first voltage application process, and
• wherein the liquid discharge apparatus is configured to reduce energy applied in at least one voltage reversal application operation such that the energy applied is less than energy applied in an immediately preceding voltage reversal application operation.