Inkjet Head Controller for Uniform Nozzle Cleaning
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Solution Overview
Problem
Inkjet heads struggle to simultaneously discharge ink from all ejection openings due to varying ink-discharge resistances, leading to unnecessary ink leakage and consumption during cleaning operations.
Innovation Solution
A liquid ejection apparatus with a controller that manages channel resistance and liquid supply to ensure uniform pressure across all ejection openings, using a circulation control phase to remove air bubbles and foreign matter before increasing pressure for efficient ink discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink pressure is increased to discharge ink from all ejection openings simultaneously, then cleaning efficiency is improved, but ink leakage occurs due to excessive pressure
Solution Approach 1:
Air bubbles are removed from the ink channels before the ink pressure is increased for cleaning. The air communication device opens the air communication passage in advance to allow air bubbles to escape, preventing them from causing ink leakage when high pressure is later applied during cleaning operations.
Solution Approach 2:
The air communication device dynamically adjusts the state of the air communication passage between open and closed states. It opens the passage to remove air bubbles, then closes it to prevent ink leakage, adapting to different operational phases to resolve the contradiction between cleaning efficiency and ink leakage prevention.
2Loss of time
If ink pressure is increased rapidly to clean all nozzles at once, then cleaning time is reduced, but air bubbles cause uneven ink discharge
Solution Approach 1:
Air bubbles are removed from the ink channels before high-pressure cleaning begins. By opening the air communication passage in advance, air bubbles are allowed to escape, ensuring that when ink pressure is subsequently increased, uniform ink discharge occurs across all ejection openings without delays or inconsistencies.
Solution Approach 2:
The system maintains continuous operation by removing air bubbles before cleaning, ensuring that the subsequent high-pressure ink discharge proceeds without interruption or unevenness. This preliminary air removal enables sustained, uniform ink flow throughout the cleaning process.
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 allows for efficient and simultaneous discharge of ink and air bubbles from all ejection openings, preventing unnecessary ink consumption and ensuring consistent cleaning performance.
Implementation Method 1
an air communication device configured to communicate an inside of the tank with an ambient air or interrupt the communication of the inside of the tank with the ambient air
Implementation Method 2
a supply pump is operated to pressurize the ink in the ink channels for a predetermined length of time, thereby discharging the ink from nozzles
Implementation Method 3
an adjusting device configured to adjust a channel resistance value of the return channel between a predetermined minimum value and a predetermined maximum value
Data Source
AI summary
A liquid ejection apparatus including: a liquid ejection head including: an inside channel; and ejection openings; a supply channel; a return channel; a supply device; an adjusting device; and a controller, wherein the controller performs a liquid circulation control for circulating liquid through the supply channel, the inside channel, and the return channel in order by controlling (i) the adjusting device such that a channel resistance value of the return channel is less than a predetermined maximum value and (ii) the supply device to supply the liquid into the inside channel, wherein, when the liquid is circulated by the liquid circulation control, the controller starts a liquid discharge control for discharging the liquid by making the channel resistance value larger than that in the liquid circulation control, and wherein the controller controls the supply device such that an amount of the liquid supplied to the inside channel per unit time in the liquid discharge control is larger than that in the liquid circulation control.