Liquid Discharge Head Startup Control for Stable Coating
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Solution Overview
Problem
Existing liquid discharge apparatuses experience a deterioration in liquid application quality due to thixotropy and liquid pressure drop during the start of liquid application, particularly in coating applications.
Innovation Solution
The liquid discharge apparatus performs a dummy discharge operation before printing, adjusting the number of nozzles and total amount of liquid discharged to stabilize viscosity and pressure, ensuring a stable discharge immediately after the start of coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid discharge starts immediately without preliminary operation, then productivity is improved, but liquid application quality deteriorates due to thixotropy and pressure drop
Solution Approach 1:
The patent applies preliminary action by performing a dummy discharge operation before the actual coating process. The controller causes the discharge head to discharge liquid to a predetermined location (receptacle or waste area) prior to starting the coating operation. This preliminary discharge stabilizes the liquid pressure and viscosity, ensuring that when the actual coating begins, the liquid application quality is maintained at a consistent level without deterioration.
2Manufacturing precision
If dummy discharge operation is performed to stabilize viscosity and pressure, then liquid application quality is improved, but loss of time occurs before printing
Solution Approach 1:
The system performs self-service by automatically executing the dummy discharge operation through the controller without requiring manual intervention. The controller monitors the system state and automatically initiates the preliminary discharge when conditions indicate it is needed, then seamlessly transitions to the coating operation. This automated approach minimizes the perceived time loss by eliminating setup and adjustment delays.
3Stability of the object's composition
If number of nozzles and liquid amount are adjusted during dummy discharge, then viscosity and pressure stability are improved, but device complexity increases
Solution Approach 1:
The patent implements feedback control where the controller monitors the discharge operation and adjusts the number of active nozzles and liquid discharge amount based on the stabilization needs. During the dummy discharge phase, the controller can selectively activate different numbers of nozzles and control the discharge rate to optimize viscosity and pressure stability. This feedback mechanism allows dynamic adjustment without requiring complex hardware modifications, as the control system adapts parameters based on observed performance.
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
This approach maintains a stable viscosity and pressure of the liquid, preventing deterioration in coating quality and ensuring consistent application.
Implementation Method 1
a liquid application quality of the liquid discharge apparatus may deteriorate due to the thixotropy of the liquid and a liquid pressure drop caused by the liquid discharge at a start of application of the liquid
Data Source
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AI summary
A liquid discharge apparatus (200) includes a liquid discharge head (10) that discharges a liquid from multiple nozzle holes to apply the liquid to an object and circuitry (500) that causes the liquid discharge head (10) to discharge the liquid from a first number of the multiple nozzle holes to a first area at a start of an application of the liquid to the object as a first discharge, discharge a first total amount of the liquid to a receptacle different from the object before the first discharge as a first dummy discharge, discharge the liquid from a second number of the multiple nozzle holes to a second area at the start of the application as a second discharge, discharge a second total amount of the liquid larger than the first total amount to the receptacle before the second discharge as a second dummy discharge. The second number is larger than the first number.