Method of driving inkjet head, and inkjet recording device

A method of driving an inkjet head having a nozzle that discharges ink and a pressure generator that, in response to application of drive signals, provides pressure changes for ink in a pressure chamber that communicates with the nozzle to cause the ink to be discharged from the nozzle, a plurality of droplets of the ink discharged from the nozzle in response to application of a series of the drive signals being caused to hit a recording medium to form a single pixel, the method comprising:

• applying the series of the drive signals to the pressure generator, the series of the drive signals including a first one of the drive signals that has a first voltage amplitude and a second one of the drive signals that has a second voltage amplitude larger than the first voltage amplitude, wherein
• a last drive signal in the series of the drive signals is the second one of the drive signals, and
• the first voltage amplitude and the second voltage amplitude are determined such that a ratio Va/Vb has a value corresponding to a viscosity of the ink to be discharged from the nozzle, where Va indicates the first voltage amplitude, and Vb indicates the second voltage amplitude;
• wherein the first voltage amplitude and the second voltage amplitude are determined so as to satisfy 0.60<Va/Vb<0.91 in a case where the viscosity of the ink to be discharged from the nozzle is more than or equal to 8 cP and less than or equal to 16 cP.

An inkjet recording device including an inkjet head having a nozzle that discharges ink and a pressure generator that, in response to application of drive signals, provides pressure changes for ink in a pressure chamber that communicates with the nozzle to cause the ink to be discharged from the nozzle, a plurality of droplets of the ink discharged from the nozzle in response to application of a series of the drive signals being caused to hit a recording medium to form a single pixel, the inkjet recording device comprising:

• a driver that applies the series of the drive signals to the pressure generator, the series of the drive signals including a first one of the drive signals that has a first voltage amplitude and a second one of the drive signals that has a second voltage amplitude larger than the first voltage amplitude, wherein
• a last drive signal in the series of the drive signals is the second one of the drive signals, and
• the first voltage amplitude and the second voltage amplitude are determined such that a ratio Va/Vb has a value corresponding to a specific gravity of the ink to be discharged from the nozzle, where Va indicates the first voltage amplitude, and Vb indicates the second voltage amplitude;
• wherein the first voltage amplitude and the second voltage amplitude are determined so as to satisfy 0.75<Va/Vb<0.86 in a case where the specific gravity of the ink to be discharged from the nozzle is more than or equal to 1.0 g/cm3 and less than or equal to 1.9 g/cm3.

An inkjet recording device including an inkjet head having a nozzle that discharges ink and a pressure generator that, in response to application of drive signals, provides pressure changes for ink in a pressure chamber that communicates with the nozzle to cause the ink to be discharged from the nozzle, a plurality of droplets of the ink discharged from the nozzle in response to application of a series of the drive signals being caused to hit a recording medium to form a single pixel, the inkjet recording device comprising:

• a driver that applies the series of the drive signals to the pressure generator, the series of the drive signals including a first one of the drive signals that has a first voltage amplitude and a second one of the drive signals that has a second voltage amplitude larger than the first voltage amplitude, wherein
• a last drive signal in the series of the drive signals is the second one of the drive signals, and
• the first voltage amplitude and the second voltage amplitude are determined such that a ratio Va/Vb has a value corresponding to a viscosity of the ink to be discharged from the nozzle, where Va indicates the first voltage amplitude, and Vb indicates the second voltage amplitude;
• wherein the first voltage amplitude and the second voltage amplitude are determined so as to satisfy 0.60<Va/Vb<0.91 in a case where the viscosity of the ink to be discharged from the nozzle is more than or equal to 8 cP and less than or equal to 16 cP.