Liquid Ejecting Apparatus Passage Resistance Equalization
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in maintaining consistent flow rates and pressures between multiple liquid ejecting heads, leading to instability in ink temperature and ejection performance due to differences in passage resistances and flow rates.
Innovation Solution
The apparatus features a tank system with specific passage configurations, including a third passage connecting to both heads, where the passage length and cross-sectional area are optimized to equalize resistance and flow rates, and a heating unit to maintain stable ink temperature, along with a depressurizing unit to control pressure and prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common passage connects to multiple liquid ejecting heads, then liquid supply is simplified, but differences in passage resistance cause inconsistent flow rates and pressure between heads
Solution Approach 1:
The patent applies local quality by making the fourth passage (connecting to first head) have much larger passage resistance than the fifth passage (connecting to second head). This localized differentiation in passage resistance compensates for the different distances from the tank, ensuring that both heads receive liquid at comparable pressures and flow rates despite their different positions in the passage network.
2Ease of operation
If passage lengths from tank to different heads are different, then heads are positioned at different locations, but this creates pressure and flow rate differences between heads
Solution Approach 1:
The patent employs asymmetry by intentionally creating unequal passage resistances in the fourth and fifth passages. The fourth passage has much larger resistance to compensate for its shorter length from the tank, while the fifth passage has smaller resistance to compensate for its longer length. This asymmetric design balances the pressure and flow rate delivered to each head, ensuring consistent ejection performance despite different head positions.
3Quantity of substance
If liquid flow rate to a head exceeds ejection capacity, then supply is sufficient, but backward flow can occur causing temperature instability
Solution Approach 1:
The patent applies parameter changes by controlling the flow rate of liquid supplied to each head through carefully designed passage resistances. By making the fourth passage resistance much larger than the fifth, the system regulates the flow rate to match or slightly exceed ejection capacity without causing excessive backflow, thereby maintaining stable liquid temperature and consistent ejection performance.
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 ensures stable ejection performance by maintaining consistent flow rates and pressures between heads, preventing temperature instability and ensuring efficient ink supply, thereby enhancing printing quality and reliability.
Implementation Method 1
a heating unit heating the liquid to supply heated liquid to the liquid ejecting heads
Implementation Method 2
A passage resistance of the fourth passage is much larger than a passage resistance from the tank to the first position
Data Source
AI summary
A liquid ejecting apparatus includes a first passage through which liquid flows from a tank to liquid ejecting heads; and a second passage through which liquid flows from the heads to the tank. The first passage includes a third passage connecting to the tank, a fourth passage branching from the third passage at a first position to allow the third passage to communicate with a first head, and a fifth passage branching from the third passage at a second position to allow the third passage to communicate with a second head. The lengths, cross-sectional areas, and resistances of various passages are set relative to others.