Printhead Orifice Humidity Control for Stable Ink Discharge
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Solution Overview
Problem
The concentration of solid components in liquid discharge heads, such as ink, increases over time due to evaporation of volatile components, leading to discharge failures, and humidity variations within the printing apparatus affect the accuracy of humidity detection near the orifices.
Innovation Solution
A printing apparatus is equipped with a blowing unit to stabilize humidity near the orifices, a detection unit to measure humidity, and a control unit to adjust ink concentration based on accurate humidity readings, improving the correlation between detected humidity and actual orifice humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discharge head is kept without liquid discharge for a long time, then the volatile component evaporates and solid component concentration increases, but discharge failure occurs
Solution Approach 1:
The system performs preliminary detection of humidity near the orifices before discharge failure occurs. The humidity sensor monitors the environment proactively, allowing the control unit to estimate solid component concentration in advance and take preventive measures such as circulation or discharge operations before discharge failure happens.
Solution Approach 2:
The system establishes a feedback loop where the humidity sensor continuously monitors humidity near the orifices, the control unit estimates solid component concentration based on humidity data, and adjusts circulation or discharge operations accordingly. This closed-loop control prevents discharge failure by maintaining optimal liquid conditions.
2Measurement precision
If humidity is detected in the printing apparatus, then the concentration of solid component can be estimated, but a difference is generated between detection result and actual humidity near the orifices due to liquid discharge
Solution Approach 1:
Instead of using a single general humidity sensor, the patent places the humidity sensor specifically near the orifices of the discharge head. This localized positioning ensures that the sensor measures the humidity environment that directly affects the liquid in the discharge head, providing accurate data for solid component concentration estimation without being influenced by humidity variations from discharged liquid.
Solution Approach 2:
The humidity sensor acts as an intermediary that indirectly measures the state of the liquid in the discharge head by monitoring the humidity environment near the orifices. This indirect measurement approach allows the system to estimate solid component concentration without directly contacting the liquid, avoiding contamination while maintaining measurement accuracy.
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 estimating ink concentration, reducing wasteful ink consumption and preventing discharge failures by stabilizing humidity near the orifices and using precise concentration control.
Implementation Method 1
a blowing unit configured to blow air to the orifice
Implementation Method 2
a detection unit configured to detect a humidity of the air
Implementation Method 3
a volatile component in the liquid evaporates from orifices
Data Source
AI summary
A printing apparatus includes a moving unit configured to relatively move a print medium and a discharging unit including an orifice configured to discharge a liquid to the print medium, a blowing unit configured to blow air to the orifice, and a detection unit configured to detect a humidity of the air.