Liquid Ejecting Head Abnormality Detection via Residual Vibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting abnormalities in liquid ejecting heads, particularly when multiple nozzles are ejecting ink simultaneously, struggle to accurately identify issues that cause disturbances in droplet velocities, leading to printing irregularities.
Innovation Solution
A method involving a liquid ejecting head with a pressure chamber, electrodes, and a piezoelectric body, where a constant voltage is held between electrodes for one ejecting portion and a drive signal with a pressure fluctuation is applied to another, allowing for the detection of residual vibrations to determine abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If residual vibration is sequentially detected from each pressure chamber to detect ejection abnormality, then ejection abnormality of each nozzle can be detected, but velocities of subsequent droplets are disturbed causing printing irregularities
Solution Approach 1:
The patent divides the detection process into separate time periods: a first period for maintaining normal ejection operations, and a second period for detecting residual vibrations. This temporal segmentation allows abnormality detection without interfering with droplet ejection velocities, resolving the contradiction between detection accuracy and printing stability.
Solution Approach 2:
The patent performs preliminary actions by maintaining constant voltage on the first electrode during the first period before detection, ensuring normal ejection operations occur first. This preliminary normal operation establishes a baseline that enables subsequent detection without causing velocity disturbances during actual printing.
2Reliability
If constant voltage is held on one electrode and drive signal is applied to another, then residual vibration can be detected without disturbing droplet ejection, but detection timing must be separated into different periods
Solution Approach 1:
The patent implements periodic detection cycles alternating between a first period (for normal operation with constant voltage) and a second period (for detection with drive signal application). This periodic structure enables systematic abnormality detection while maintaining printing reliability during the first period, accepting controlled time loss for comprehensive system monitoring.
3Productivity
If drive signal is continuously applied to all ejecting portions, then continuous droplet ejection is achieved, but residual vibration interferes with abnormality detection
Solution Approach 1:
The patent extracts the detection function from the continuous ejection process by applying drive signals only to specific ejecting portions during designated second periods, while other portions maintain constant voltage during first periods. This extraction allows residual vibration detection without continuous interference from ongoing ejection operations.
Solution Approach 2:
The patent dynamically adjusts the operational state of different ejecting portions over time, switching between constant voltage mode (first period) and drive signal mode (second period). This dynamic control enables the system to alternate between maintaining ejection capability and performing detection, resolving the conflict between continuous productivity and accurate 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 approach effectively identifies abnormalities in the liquid ejecting head, reducing printing irregularities by accurately detecting disturbances in droplet velocities and enabling timely maintenance.
Implementation Method 1
a piezoelectric body that is disposed between the first electrode and the second electrode and is driven to apply a pressure fluctuation to the liquid in the pressure chamber
Implementation Method 2
detecting a residual vibration, which is a vibration of the liquid in the pressure chamber of the first ejecting portion
Data Source
AI summary
An abnormality determination method for a liquid ejecting head including a plurality of ejecting portions including a nozzle, a pressure chamber, a first electrode, a second electrode, and a piezoelectric body, and a liquid storage portion that communicates with each of the plurality of ejecting portions, the method including: holding a voltage between the first electrode and the second electrode of a first ejecting portion at a constant voltage in a first period; supplying a drive signal for applying a pressure fluctuation to the liquid in the pressure chamber of a second ejecting portion, to one of the first electrode and the second electrode of the second ejecting portion in the first period; detecting a residual vibration of the first ejecting portion, in a second period following the first period; and determining whether or not the liquid ejecting head has an abnormality based on the residual vibration.