Liquid Ejection Head Vibration Timing for Nozzle Thickening Control
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Solution Overview
Problem
Existing liquid ejecting apparatuses experience a decrease in ejection property due to liquid thickening caused by solvent evaporation, despite circulation and minute vibration operations.
Innovation Solution
A liquid ejecting apparatus with a circulation control section and a minute vibration control section, where the circulation operation starts at a first time and the minute vibration operation starts earlier at a second time, using a drive signal with a specific waveform to control the liquid's vibration in the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circulation operation and minute vibration operation are performed simultaneously or in conventional sequence, then liquid thickening is addressed, but ejection property still decreases due to insufficient prevention of local thickening
Solution Approach 1:
The circulation operation is started before the minute vibration operation to preliminarily circulate the liquid through the flow path, preventing thickening at the upstream side of the nozzle before vibration is applied. This sequential timing ensures that liquid is continuously moved through the system, maintaining uniform viscosity and preventing local thickening that would otherwise occur during vibration alone.
Solution Approach 2:
The system employs periodic circulation operations interspersed with minute vibration operations rather than continuous operation. The circulation is periodically activated to refresh liquid in the flow path, followed by vibration periods for maintaining nozzle readiness. This periodic alternation prevents cumulative thickening effects while maintaining ejection capability.
2Manufacturing precision
If minute vibration operation is performed to eliminate local thickening, then ejection amount improves, but liquid may be inadvertently ejected during vibration
Solution Approach 1:
The minute vibration operation applies only the necessary degree of vibration intensity to prevent and eliminate local thickening without exceeding the threshold that would cause liquid ejection. The vibration amplitude and frequency are carefully controlled to be sufficient for maintaining liquid uniformity in the nozzle while remaining below the level that would generate droplet ejection.
Solution Approach 2:
The system dynamically adjusts vibration parameters (amplitude, frequency, duration) based on operational conditions to maintain optimal effectiveness. By changing these parameters, the system achieves sufficient vibration to prevent thickening while staying below the ejection threshold, adapting to different liquid properties and environmental conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents liquid thickening and maintains ejection performance by controlling the circulation and vibration operations to prevent liquid ejection, enhancing the apparatus's ejection capability.
Implementation Method 1
a first piezoelectric element that is driven in response to supply of a drive signal, a first nozzle that ejects liquid by means of a pressure that is applied when the first piezoelectric element is driven
Implementation Method 2
a circulation control section that controls a circulation operation of circulating the liquid in the first individual flow path
Implementation Method 3
a minute vibration control section that supplies a drive signal having a first waveform to the first piezoelectric element so as to control a minute vibration operation of causing the liquid in the first nozzle to vibrate to such a degree that the liquid is not ejected from the first nozzle
Data Source
AI summary
A liquid ejecting apparatus includes a liquid ejection head, a circulation control section that controls a circulation operation of circulating the liquid in the first individual flow path, and a minute vibration control section that supplies a drive signal having a first waveform to the first piezoelectric element so as to control a minute vibration operation of causing the liquid in the first nozzle to vibrate to such a degree that the liquid is not ejected from the first nozzle. The circulation control section starts the circulation operation at a first time, and the minute vibration control section starts the minute vibration operation at a second time earlier than the first time.