Ink Jet Nozzle Viscosity Control via Circulation Path
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Solution Overview
Problem
Existing ink jet technologies face challenges in maintaining ink ejection properties due to increased viscosity near the nozzle exit, as they do not adequately consider the shape of the nozzle and position of the circulation flow path, leading to reduced ink removal and degraded ejection performance.
Innovation Solution
The ink jet driving apparatus and method involve setting the ink withdrawal amount based on the nozzle shape and circulation flow path position, ensuring the circulation flow path is positioned close to the nozzle exit, with a distance not exceeding 3.47 times the nozzle diameter, to effectively remove viscous ink and prevent ejection property degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink is circulated via circulation flow path part to prevent viscosity increase, then ink ejection properties are maintained, but the circulation flow path part must be positioned very close to the nozzle (N ≤ 3.47D), which complicates the structural design
Solution Approach 1:
The circulation flow path part is positioned at a specific location relative to the nozzle exit (distance N ≤ 3.47D) to create optimal local conditions for ink circulation. This localized positioning ensures effective ink removal while maintaining manageable structural complexity
Solution Approach 2:
Ink circulation is performed during the non-ejection time period before viscosity increase becomes problematic. By proactively circulating ink during idle periods, the system prevents viscosity buildup without interfering with the ejection function
2Object-affected harmful factors
If non-ejection pulse is applied to oscillate meniscus during non-ejection time, then ink drying is prevented, but ink viscosity still increases and ejection speed degrades
Solution Approach 1:
Ink circulation is continuously performed during the non-ejection time period, maintaining constant ink flow through the circulation path. This continuous action ensures ink remains fluid and prevents both drying and viscosity increase, preserving ejection speed
Solution Approach 2:
The circulation flow path part acts as an intermediary system that diverts ink flow away from the nozzle during non-ejection periods. This intermediate circulation path allows ink to be actively managed separately from the ejection function, addressing both drying prevention and viscosity control
3Quantity of substance
If circulation flow path part is disposed diverging from ink flow path, then ink circulation is achieved, but ink withdrawal amount is insufficient and viscous ink accumulates in nozzle
Solution Approach 1:
The position parameter of the circulation flow path part is optimized (distance N ≤ 3.47D from nozzle exit) to maximize ink withdrawal efficiency. By carefully controlling this geometric parameter, sufficient ink is drawn into the circulation path while maintaining reliable ejection properties
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 approach enhances the possibility of successfully removing viscous ink from the nozzle, maintaining ejection performance and reducing waste ink, while allowing for high-density nozzle arrangements without significant ejection speed reduction.
Implementation Method 1
a piezoelectric actuator (such as a piezoelectric, electrostatic, or thermal deformation actuator)... In particular, to achieve a compact, low-cost, high-resolution (achievable with small ink droplets) printer, it is suitable to adopt an ink jet head that uses a thin-film piezoelectric element
Implementation Method 2
a piezoelectric actuator... causes an ink meniscus in a nozzle to oscillate during a non-ejection time
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
When a diameter of a hole at an exit (211a) of a nozzle (211) is expressed as D (µm) and a distance between a position in a circulation flow path part (213) on a side thereof closest to the exit (211a) and the exit (211a) is expressed as N (µm) in an ink jet driving apparatus, N ≤ 3.47D is satisfied. During non-ejection, a driving control unit generates a driving signal for withdrawing ink from the exit (211a) of the nozzle (211) to a side of a pressure chamber (231) through a distance of 0.16N or more and 0.555D or less, and for causing the ink meniscus to oscillate, and applies the driving signal to a driving element.