Inkjet apparatus and method for manufacturing organic EL device

1. An inkjet device, comprising:

an inkjet head having an ink reservoir storing an ink, a pressure applier applying pressure to the ink in the ink reservoir, and a nozzle discharging the ink from the ink reservoir as an ink drop; and

a discharge controller controlling pressure application by the pressure applier, wherein

the pressure applier executes the pressure application to perform:

a standby drive operation of applying a standby oscillation to the ink, an amplitude direction matching a discharge direction within a range that does not cause the ink to be discharged from the nozzle; and

a main drive operation of applying a main oscillation to the ink, the amplitude direction matching the discharge direction within a range that causes the ink to be discharged from the nozzle, and the main drive operation being performed after the standby drive operation,

the main drive operation is performed during a resonance state occurring after the standby drive operation and after application of a resonance oscillation causing resonance in the standby oscillation,

a start time of the main drive operation occurs within a time interval where a displacement by the standby drive operation is oriented toward an interior of the nozzle,

the pressure applier includes a piezoelectric element,

the discharge controller controls the pressure application by the pressure applier by controlling a voltage signal applied to the piezoelectric element,

a waveform of the voltage signal includes a standby oscillatory waveform portion for executing the standby drive operation, and a main oscillatory waveform portion for executing the main drive operation,

the main oscillatory waveform portion includes a first period of changing voltage to apply the resonance oscillation, and a second period of changing voltage to apply the main oscillation, and

a time interval X between the first period and the second period is set using a time T required for Helmholtz resonance, and satisfies −0.5T+2nT≦X≦0.5T+2nT (where n is a natural number including zero) with a value that is greater than zero.

2. The inkjet device of claim 1 , wherein

a voltage change A of the voltage signal when applied to the piezoelectric element causing the standby oscillation of the ink during the standby drive operation is set proportionately to a voltage change B of the voltage signal when applied to the piezoelectric element causing the main oscillation of the ink during the main drive operation, and satisfies 0%<A/B ≦20%.

3. The inkjet device of claim 1 , wherein

for a discharge speed of the ink being discharged from the nozzle by the main drive operation,

an initial speed V 0 , defined as a speed of the ink passing a tip of the nozzle, and an initial speed V 0 ′, defined as the speed of the ink under identical conditions except that the standby drive operation is not executed, satisfy 50%≦V 0 /V 0 ′<100%.

4. A manufacturing method for an organic electroluminescence device, comprising:

forming a first electrode over a substrate;

forming a functional layer that includes a light-emitting layer over the first electrode; and

forming a second electrode over the functional layer, wherein

at least for the light-emitting layer, the forming of the functional layer involves applying an ink that includes a formation material and a solvent and then drying the ink by causing the solvent to evaporate, and

the ink is applied using the inkjet device of claim 1 .