Liquid Discharge Head Flow Resistance Balancing
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Solution Overview
Problem
Existing liquid discharge heads face difficulties in implementing simultaneous suction recovery due to varying flow resistances in paths from liquid tanks to discharge ports, making it challenging to set a well-balanced suction amount across multiple flow paths.
Innovation Solution
The liquid discharge head is designed with multiple discharge port groups connected to separate flow paths, where the flow resistance ratio between the highest and lowest paths is set to 4 or less, allowing for simultaneous suction recovery by adjusting the size and arrangement of discharge ports and the length of flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous suction recovery is performed for multiple discharge port arrays, then air bubble removal efficiency is improved, but flow resistance variation among flow paths causes unbalanced suction amounts
Solution Approach 1:
The patent adjusts flow resistance parameters by modifying discharge port dimensions (diameter, area) and flow path characteristics (length, cross-section) to achieve a balanced suction state. Specifically, discharge ports are designed with different diameters or areas to compensate for variations in flow path resistance, ensuring that suction amounts remain balanced across all flow paths during simultaneous recovery operations.
2Quantity of substance
If discharge port sizes are varied among discharge port arrays, then flow resistance differences are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by assigning different discharge port dimensions to different discharge port arrays based on their specific flow resistance requirements. Each discharge port array is locally optimized with appropriate port sizes to balance flow resistance, rather than using uniform dimensions across all arrays. This localized differentiation achieves flow balance while maintaining manufacturing feasibility through standardized production techniques.
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 design enables effective simultaneous suction recovery across multiple flow paths, reducing waste ink and operational costs by maintaining a balanced suction pressure, ensuring efficient air bubble removal without drawing liquid from the tanks.
Implementation Method 1
depressurizing the inside of the cap by a suction pump
Implementation Method 2
performs a suction recovery process for removing a formed air bubble by suction
Implementation Method 3
Flow resistance in a path from the liquid tank to the discharge port
Data Source
AI summary
A liquid discharge head includes a recording element substrate having first to fourth discharge port groups, each of which includes a plurality of discharge ports for discharging liquid, first flow path connecting a first liquid tank to the first discharge port group, a second flow path connecting a second liquid tank to the second discharge port group, and a third flow path connecting a third liquid tank to the third discharge port group and the fourth discharge port group, wherein a flow resistance in the first flow path is smaller than a flow resistance in the second flow path and larger than a flow resistance in the third flow path, and wherein a ratio of the flow resistance in the second flow path to the flow resistance in the third flow path is 4 or less.