Inkjet Recording Head Ejection Failure Detection
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Solution Overview
Problem
Existing inkjet recording apparatuses face challenges in accurately determining ejection failure due to unstable temperature changes in the recording element, particularly at high altitudes or locations with low atmospheric pressure, leading to decreased detection accuracy.
Innovation Solution
A recording apparatus with a liquid ejection head featuring a heating element, protection layers, electrodes, and a temperature detection element, where the potential settings for the electrodes vary during detection of a feature point in the temperature curve, allowing for precise determination of ejection failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature detection is performed by monitoring temperature drop when liquid droplet contacts recording element, then ejection state can be detected, but detection accuracy decreases in low atmospheric pressure environments
Solution Approach 1:
The patent introduces an intermediary substance (liquid with specific physical properties) between the recording element and the external environment. This liquid mediates the heat transfer process, ensuring stable thermal interaction regardless of atmospheric pressure conditions. The liquid's thermal properties act as a buffer that stabilizes the temperature detection signal.
Solution Approach 2:
The patent changes the detection parameter from direct temperature drop monitoring to monitoring the time until a predetermined temperature is reached. This parameter transformation converts an unstable measurement (temperature drop magnitude) into a stable measurement (time duration), which is less affected by atmospheric pressure variations.
2Measurement precision
If liquid droplet contact with recording element is used for temperature decrease, then ejection detection is enabled, but contact stability becomes problematic in certain nozzle dimensions
Solution Approach 1:
The system uses the ejected liquid itself to perform the detection function. The liquid that is naturally ejected for printing purposes also serves as the thermal medium for detection, eliminating the need for separate detection mechanisms. This self-service approach ensures consistent contact stability since the liquid's ejection behavior is inherently controlled by the nozzle design.
Solution Approach 2:
The patent merges the ejection function and detection function into a single integrated process. The same liquid ejection event that deposits material also provides the thermal contact needed for detection. By combining these functions, the system eliminates the instability associated with separate detection mechanisms and utilizes the naturally occurring liquid contact.
3Ease of operation
If inflection point detection is used in temperature curve, then normal ejection can be identified, but detection accuracy decreases when temperature drop is unstable
Solution Approach 1:
The patent performs preliminary action by pre-setting a predetermined temperature threshold before the detection process begins. This predetermined value serves as a reference point that guides the detection process, allowing the system to determine ejection state based on when the temperature reaches this predetermined level, rather than relying on post-detection analysis of inflection points.
Solution Approach 2:
The patent replaces the mechanical/visual analysis method (inflection point detection on temperature curves) with a threshold-based temporal measurement system. Instead of analyzing the shape and derivatives of temperature curves, the system simply measures the time duration until a predetermined temperature is reached, substituting complex curve analysis with a simpler, more stable temporal measurement.
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 configuration enhances the accuracy of ejection state determination and failure identification, improving the reliability of the recording process even under unstable conditions.
Implementation Method 1
a heating element that generates thermal energy required to eject liquid
Implementation Method 2
a temperature detection element that corresponds to the heating element, and a detection unit configured to detect a feature point in a temperature curve that is obtained by the temperature detection element
Implementation Method 3
this inflection point is assumed to occur in the case where a rear end of an ejected liquid droplet comes into contact with the recording element and cools the recording element
Data Source
AI summary
A recording apparatus includes: a liquid ejection head including a heating element, a first protection layer that blocks contact between the heating element and liquid, a second protection layer that covers at least a portion of the first protection layer to be heated by the heating element and that functions as a first electrode, a second electrode that is electrically connected to the first electrode through the liquid, an ejection port that ejects the liquid, and a temperature detection element that corresponds to the heating element, and a detection unit configured to detect a feature point in a temperature curve that indicates a relationship between time and temperature, in which a combination of a potential set for the first electrode and a potential set for the second electrode in a case where printing is performed varies from that in a case where the detection unit detects the feature point.