Liquid circulation device and liquid discharge device

A liquid discharge device, comprising:

• a liquid discharge head configured to discharge liquid;
• a booster pump configured to draw liquid from a liquid replenishing tank and to supply the liquid to the liquid discharge head;
• a pressure reducing pump configured to collect the liquid from the liquid discharge head and to supply the liquid to the liquid replenishing tank;
• a buffer tank connected between the liquid discharge head and the booster pump and between the liquid discharge head and the pressure reducing pump, and into which the liquid flows;
• a pressure sensor configured to detect pressure in the buffer tank;
• and
• a processor configured to control driving voltages of the booster pump and the pressure reducing pump based on a nozzle surface pressure of the liquid discharge head calculated based on pressure data detected by the pressure sensor, and to determine whether or not the liquid is deficient based on the nozzle surface pressure, the driving voltage of the booster pump, and the driving voltage of the pressure reducing pump.

A liquid circulation method, comprising:

• drawing liquid from a liquid replenishing tank and supplying the liquid to a liquid discharge head;
• collecting the liquid from the liquid discharge head and supplying the liquid to the liquid replenishing tank;
• flowing the liquid into a buffer tank connected between the liquid discharge head and the booster pump and between the liquid discharge head and the pressure reducing pump;
• detecting pressure in the buffer tank;
• a processor configured to controlling driving voltages that control drawing, supplying, and collecting the liquid based on a nozzle surface pressure of the liquid discharge head calculated based on the pressure detected;
• and
• determining whether or not the liquid is deficient based on the nozzle surface pressure, the driving voltage of drawing and supplying, and the driving voltage of collecting and supplying.