Liquid Ejection Head Branch Port Notch for Temperature Uniformity
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Solution Overview
Problem
High-speed liquid ejection heads used in commercial printers face challenges with temperature differences among recording element substrates, leading to image irregularities due to heat generation and temperature control issues during standby and recording operations.
Innovation Solution
A liquid ejection head design featuring support members with low thermal conductivity and a unique branch port notch structure that creates swirling currents in liquid chambers to efficiently stir and maintain uniform liquid temperature, minimizing temperature differences and reducing heat transfer to the base substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If temperature control operation is conducted in recording standby status, then temperature uniformity is improved, but transitional temperature rise occurs at startup causing image irregularities
Solution Approach 1:
The patent applies preliminary action by pre-heating the liquid in the liquid chamber before recording starts. The temperature control means heats the liquid during standby status, and the liquid circulation system circulates the heated liquid to the recording element substrate before recording begins, preventing transitional temperature rise and image irregularities at startup.
Solution Approach 2:
The patent uses the liquid itself as an intermediary to transfer heat from the temperature control means to the recording element substrate. The liquid circulation system acts as a mediator, pumping the heated liquid from the liquid chamber through the liquid supply port to the recording element substrate, achieving uniform temperature distribution without direct thermal contact.
2Temperature
If liquid circulation is increased to reduce temperature differences, then temperature uniformity is improved, but heat transfer to base substrate increases
Solution Approach 1:
The patent segments the thermal management system into distinct functional zones: the liquid chamber for heat storage, the liquid circulation system for heat transport, and the recording element substrate for heat application. This segmentation allows controlled heat circulation that maintains temperature uniformity while minimizing unnecessary heat transfer to the base substrate through the support member.
Solution Approach 2:
The patent applies local quality by providing temperature control means specifically positioned to heat the liquid in the liquid chamber, and using the liquid circulation system to deliver heat locally to the recording element substrate where it is needed. The support member with low thermal conductivity provides local thermal insulation to prevent heat loss to the base substrate.
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 effectively suppresses temperature-related image irregularities by maintaining uniform liquid temperature, reducing heat transfer, and enhancing heat dissipation through ejected liquid, thus ensuring high-quality image recording without transitional temperature rises during startup.
Implementation Method 1
support members having a low thermal conductivity
Implementation Method 2
branch port notch structure that creates swirling currents in liquid chambers to efficiently stir and maintain uniform liquid temperature
Implementation Method 3
temperature control means, which may typically be so-called sub-heaters
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A liquid ejection head includes a plurality of ejection members, each having an ejection port for ejecting liquid, an energy generating element for generating energy to be utilized to eject liquid from the ejection port, a liquid chamber for storing liquid to be supplied to the ejection port and a heater, and a base substrate bearing the plurality of ejection members arranged thereon and having a common flow channel for supplying liquid to the plurality of liquid chambers. The common flow channel communicates with the liquid chambers by way of respective branch ports and each of the branch ports is provided with a notch portion at the upstream side thereof as viewed in the flow direction of liquid flowing through the common flow channel.