Liquid Ejection Apparatus Electrode Control for Kogation Prevention
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Solution Overview
Problem
Conventional inkjet recording methods face increased control load due to the need for precise modulation of multiple drive pulses for high-definition image formation, leading to unevenness in ink droplet ejection and image quality.
Innovation Solution
A liquid ejection apparatus with a conversion element, protection layers, and a control unit that adjusts the potential difference between electrodes to optimize ink ejection, reducing the control load by managing the ejection speed and preventing kogation through electric field control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple drive pulses are used to increase ejection speed, then bubble generation energy is increased, but control load increases due to optimal modulation needed for each pulse
Solution Approach 1:
The patent changes the electrical parameter by applying a potential difference between the first electrode (upper protection layer) and second electrode (opposing electrode) to control ink droplet ejection. This electrical field control modifies the ejection characteristics without requiring complex multi-pulse modulation, thereby reducing control load while maintaining ejection performance.
Solution Approach 2:
The patent introduces an electric field as an intermediary mechanism between the electrodes and ink droplets. This electric field acts as a mediator to control droplet ejection and prevent kogation, simplifying the control system compared to direct thermal or mechanical control methods that would require complex pulse modulation.
2Reliability
If potential difference control is implemented to prevent kogation, then ink color materials are repelled from heater periphery, but device complexity increases due to additional electrode control
Solution Approach 1:
The upper protection layer serves multiple functions: it protects the heater from ink contact and simultaneously functions as the first electrode for applying potential difference. This multi-functionality prevents kogation without requiring separate electrode structures, thereby avoiding increased device complexity.
Solution Approach 2:
The patent merges the protection layer and electrode function into a single integrated structure. The first electrode is formed by the upper protection layer itself, combining the protective barrier function with the electrical control function, thus eliminating the need for additional separate components.
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 suppresses unevenness in ink droplet ejection and improves image quality by reducing the control load and stabilizing bubble generation, ensuring consistent ejection speed across multiple recording elements.
Implementation Method 1
electrothermal conversion elements (hereinafter, also referred to as 'heaters') including heating resistive elements heat an ink and generates bubbles
Implementation Method 2
a potential control unit that forms an electric field between the upper protection layer electrode and the opposing electrode
Implementation Method 3
prevents ink color materials and resins that cause kogation and that are charged to negative potentials from being attracted to a periphery of the heater
Data Source
AI summary
An aspect of the present disclosure is a liquid ejection apparatus including: a liquid ejection head including a conversion element that generates energy required to eject liquid, a first protection layer that blocks contact between the conversion element and the liquid, a second protection layer that partially covers the first protection layer and functions as a first electrode, a second electrode that is electrically connected to the first electrode through the liquid, and an ejection port that ejects the liquid, and a control unit configured to control a potential difference between the first electrode and the second electrode in printing to a predetermined value by changing at least one of potentials of the first electrode and the second electrode. The control unit sets the potential difference based on at least one of a condition and a configuration of the liquid ejection head.