Liquid Ejecting Head Ranking and Distribution for Printer Yield
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Solution Overview
Problem
The manufacturing process of liquid ejecting apparatuses often results in lower-than-desired performance due to errors in flow channels and deformation elements, leading to significant yield deterioration, especially with larger heads like line type heads.
Innovation Solution
A method involving a check process to rank liquid ejecting heads based on performance, distributing high brightness heads to high brightness applications and low brightness heads to low brightness applications, with a control system to adjust liquid ejection amounts from low brightness heads to compensate for lower performing outlets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check is performed and discarding is performed to ensure liquid ejecting performance of each head, then liquid ejecting performance is ensured, but yield is deteriorated
Solution Approach 1:
The patent applies local quality by distributing heads with different liquid ejecting performances to different positions in the liquid ejecting apparatus. Specifically, heads with higher performance are distributed to positions requiring higher performance (such as line type heads), while heads with lower performance are distributed to positions where lower performance is acceptable (such as dot type heads). This ensures that each local position receives a head appropriate to its requirements, maintaining overall apparatus performance while utilizing all heads.
Solution Approach 2:
The patent changes the parameter of head distribution by classifying heads into different ranks based on their liquid ejecting performance and distributing them to different positions. The control section adjusts the ejection amount of liquid from each head based on its performance rank, thereby optimizing the overall performance of the liquid ejecting apparatus while utilizing all heads and improving yield.
2Reliability
If discarding of heads with low liquid ejecting performance is performed, then overall liquid ejecting performance is ensured, but yield deterioration is significant
Solution Approach 1:
The patent applies discarding and recovering by recovering heads that would otherwise be discarded due to lower liquid ejecting performance. Instead of discarding these heads, the control section distributes them to positions in the liquid ejecting apparatus where their performance is sufficient and adjusts the ejection amount accordingly. This recovers the value of previously discarded heads, improving yield while maintaining overall performance.
3Adaptability or versatility
If heads are classified into ranks based on check results, then appropriate distribution is enabled, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing a check on the liquid ejecting performance of each head during the manufacturing process and classifying heads into different ranks before distribution. This preliminary classification enables the control section to distribute heads to appropriate positions in advance, ensuring optimal performance matching while simplifying the distribution process. The check and classification are performed once during manufacturing, avoiding repeated complexity during operation.
Data Source
AI summary
In the manufacturing process of a printer, a check (check associated with the liquid ejecting performance of ejection outlets) on the heads is performed, and the heads are ranked based on the result of the check. The heads that are high in liquid ejecting performance are classified as a first rank; the heads that are low in liquid ejecting performance, as a second rank; and the heads that are lower in ejecting performance than the heads of the second rank, as a third rank. The heads of the third rank are dealt with as not applied to the printer. The heads of the second rank are distributed to a color inkjet head that ejects a color ink or to a pretreatment liquid ejecting head that ejects a colorless liquid. The heads of the first rank are distributed to a black inkjet head that ejects black ink.