Liquid Ejecting Head Symmetrical Nozzle Rows Pressure Fluctuation
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Solution Overview
Problem
In liquid ejecting apparatuses, the uneven timing of ink ejection from nozzle rows with different inter-nozzle distances leads to unstable ink discharge and defective printing due to varying negative pressures in the supply flow paths.
Innovation Solution
The liquid ejecting head is designed with a first and second supply flow path for each nozzle row set, where the compliance capacity of the second supply flow path is larger and the flow path resistance is smaller than the first, optimizing the ink delivery and reducing pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nozzle rows with different inter-nozzle distances are symmetrically arranged, then the printing quality is improved by aligning ink landing order, but the ink discharge stability deteriorates due to varying negative pressures in supply flow paths
Solution Approach 1:
The patent applies local quality by providing different compliance capacities to different supply flow paths based on their specific needs. The second supply flow path (supplying the outer nozzle row with longer inter-nozzle distance) is given a larger compliance capacity than the first supply flow path. This localized differentiation compensates for the timing difference in ink ejection caused by the longer distance, stabilizing ink discharge for each nozzle row according to its specific requirements while maintaining the symmetrical arrangement for printing quality.
2Area of stationary object
If the inter-nozzle row distance is increased in a nozzle row set, then the coverage area is improved, but the ink discharge timing becomes unstable due to larger timing differences
Solution Approach 1:
The patent applies parameter changes by modifying the compliance capacity parameter of the supply flow path. For the second supply flow path serving the nozzle row with longer inter-nozzle distance, a larger compliance capacity is provided to compensate for the increased timing difference. This parameter adjustment allows the system to maintain larger coverage area through extended inter-nozzle distances while stabilizing ink discharge timing by compensating for the delayed ink arrival at the nozzle.
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 stabilizes ink discharge and reduces defective printing by alleviating pressure fluctuations, ensuring consistent ink ejection across nozzle rows with different inter-nozzle distances.
Implementation Method 1
a compliance portion (49) having a flexible structure and configured to compensate for a fluctuation in pressure in the supply flow path (140)
Data Source
AI summary
A liquid ejecting head includes a first-nozzle-row set in which a pair of first-nozzle-rows is disposed in a second direction intersecting a first direction so that the first-nozzle-rows are symmetrical about a reference line extending in the first direction and a second-nozzle-row set in which a pair of second-nozzle-rows is disposed in the second direction so that the second-nozzle-rows are symmetrical about the reference line. In the second direction, the distance between the second-nozzle-rows is longer than the distance between the first-nozzle-rows. First nozzles constituting the first-nozzle-row set communicate with a first liquid supply source via a first supply flow path. Second nozzles constituting the second-nozzle-row set communicate with a second liquid supply source via a second supply flow path. Compliance capacity of the second supply flow path is larger than compliance capacity of the first supply flow path.