Liquid Ejection Head Nozzle Defect Detection via Grouped Signal Analysis
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Solution Overview
Problem
Existing liquid ejection apparatuses, such as printers, require a significant amount of time to determine whether nozzles are ejection-defective, especially when the number of nozzles is large, as they need to be driven individually to judge ink ejection functionality.
Innovation Solution
A liquid ejection apparatus with a liquid ejection head that groups nozzles into sets, using a signal output circuit to differentiate between normal and defective discharges, allowing the controller to judge nozzle conditions based on simultaneous ejections from multiple nozzles, reducing the number of times the head needs to be driven.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the head is driven individually for each nozzle to judge ink ejection functionality, then the judgment accuracy for each nozzle is improved, but the time required to perform the judgment increases significantly
Solution Approach 1:
The patent merges multiple nozzle ejection judgments into a single head driving operation. By ejecting liquids from multiple nozzles simultaneously and detecting the combined charge amount, the system judges the ejection functionality of multiple nozzles in one operation, thereby reducing the total number of driving operations required while maintaining judgment accuracy through the relationship between detected charge amount and number of defective nozzles
Solution Approach 2:
The patent introduces a detecting electrode as an intermediary that measures the charge amount of liquid droplets ejected from multiple nozzles. This intermediary measurement enables indirect judgment of multiple nozzle conditions simultaneously, converting the problem of individual nozzle detection into a collective measurement that can be analyzed to identify defective nozzles
2Productivity
If the number of nozzles is increased, then the productivity of the liquid ejection apparatus is improved, but the time required to judge all nozzles increases due to the need for individual driving
Solution Approach 1:
The patent applies merging by combining multiple nozzle judgments into single head driving operations. The detecting electrode measures the collective charge amount from multiple nozzles, and the controller analyzes this data to identify defective nozzles, reducing the total operations from N individual drivings to a smaller number of group drivings where N is the number of nozzles
Solution Approach 2:
The patent segments the nozzle group into multiple first nozzle groups, each containing two or more nozzles. This segmentation allows systematic judgment of large numbers of nozzles by dividing them into manageable groups that can be evaluated in parallel or sequence, making the scaling to high-nozzle-count systems feasible
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 significantly reduces the time required to identify ejection-defective nozzles by allowing simultaneous ejection from multiple nozzles, thereby decreasing the number of driving cycles needed for judgment.
Implementation Method 1
it is judged whether or not the ink is ejected from the nozzles on the basis of the change in the electric potential brought about on a detecting electrode in this situation
Data Source
AI summary
A liquid ejection apparatus is provided, comprising a liquid ejection head, a signal output circuit which outputs different signals depending on the number of ejection-defective nozzles in which any defective discharge of a liquid occurs, and a controller. The controller executes judgment to judge whether a first condition that any ejection-defective nozzle is absent in two or more nozzles for constructing a first nozzle group is satisfied, a second condition that all of the nozzles are the ejection-defective nozzles is satisfied, or a third condition that only some of the nozzles are the ejection-defective nozzles is satisfied, on the basis of the signal outputted from the signal output circuit.