Liquid Discharge Head Pressure Drop Control via Segmented Channels
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Solution Overview
Problem
Liquid discharge heads face challenges in reducing size while maintaining high recording quality due to increased viscosity near the discharge orifice, which affects discharge properties and image quality, and existing solutions that attempt to circulate liquid to address this issue either increase the head's size or lead to higher viscous resistance and pressure drops.
Innovation Solution
A liquid discharge head design featuring groove-shaped channels on the opposite face of the recording element board, with a liquid supply channel and cover to manage pressure drop, ensuring the pressure drop from supply openings to supply ports is 5000 Pa or less, allowing for efficient liquid replenishment and reduced size without compromising recording quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If grooves serving as channels for liquid are provided on the rear surface of the board and through channels are formed passing through the board, then the size of the liquid discharge head is reduced, but viscous resistance increases and pressure drop increases
Solution Approach 1:
The liquid discharge head is divided into multiple independent liquid supply channels, each serving specific discharge orifices. This segmentation allows optimization of each channel's dimensions to reduce viscous resistance while maintaining compact overall size. The channels are divided into first liquid supply channels for initial liquid supply and second liquid supply channels for replenishment, allowing independent optimization of each path.
Solution Approach 2:
Liquid supply channels are formed in the thickness direction (third dimension) of the board rather than only on the surface. Through-holes penetrating the board thickness provide direct liquid supply paths, reducing the need for long surface grooves and thereby reducing viscous resistance and pressure drop while maintaining compact head size.
2Volume of moving object
If the board is made smaller to reduce head size, then the channels become narrower, but viscous resistance increases and pressure drop increases
Solution Approach 1:
The liquid supply system is segmented into multiple independent channels (first liquid supply channels and second liquid supply channels) that can be independently designed and optimized. This allows each channel to have appropriate dimensions for low viscous resistance while the overall head remains compact. The segmentation enables parallel liquid supply paths, reducing the burden on individual channel dimensions.
Solution Approach 2:
A liquid supply channel forming member is introduced as an intermediary component that integrates the liquid supply channels. This member can be separately manufactured with optimized channel dimensions and then assembled to the board, allowing complex channel configurations to be achieved without increasing head size. The intermediary component separates the channel design complexity from the overall head structure.
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
The design enables a compact liquid discharge head with improved liquid replenishment speed and maintained recording quality by controlling pressure drop within the specified limit, preventing image quality deterioration and allowing for high-density recording.
Implementation Method 1
a sum P1 of pressure drop of liquid on the liquid supply channel from any supply-side opening to a supply port communicating with the supply-side opening and at a farthest removed position from the supply-side opening, and pressure drop of liquid at the supply port at the farthest removed position, is 5000 Pa or less
Data Source
AI summary
Multiple recording elements are disposed on one face of a recording element board, and a groove-shaped liquid supply channel is provided on the other face in common for the recording elements. Multiple supply ports passing through the recording element board and communicating the liquid supply channel with pressure chambers, and supply-side openings serving as supply ports of liquid to the liquid supply channel are further provided. When discharging liquid, the sum of pressure drop of the liquid from any supply-side opening to the supply port at a position farthest removed from that supply-side opening, and the pressure drop of the liquid at the supply port, is 5000 Pa or less.