Inkjet Recording Method Stabilizing Aqueous Ink Ejection
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Solution Overview
Problem
Inkjet recording methods face challenges in maintaining discharge stability due to large differences in dynamic and static surface tensions of aqueous ink, leading to nozzle stream bending and streaks in printed materials, resulting in degraded image quality.
Innovation Solution
An inkjet recording method that uses aqueous ink with a dynamic surface tension at least 10 mN/m higher than static surface tension, and a two-stage meniscus drawing pulse in the nozzle before discharge, to stabilize ink ejection and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aqueous ink with large difference between dynamic and static surface tension is used, then penetrability into recording member is improved, but discharge stability deteriorates
Solution Approach 1:
The patent applies preliminary action by forming a meniscus in advance within the nozzle before actual droplet ejection. The meniscus is created by applying a first drive signal that draws ink into the nozzle and forms a curved surface, preparing the ink for stable subsequent ejection. This preliminary meniscus formation ensures that the ink is properly positioned and tension-balanced before the second ejection signal is applied, resolving the contradiction between penetrability and discharge stability.
Solution Approach 2:
The patent segments the ejection process into two distinct phases: meniscus formation (first drive signal) and droplet ejection (second drive signal). By dividing the single ejection action into two sequential steps, the system can optimize each phase independently - the first phase prepares the ink meniscus for stable tension, while the second phase performs the actual ejection, thereby resolving the surface tension contradiction.
2Manufacturing precision
If static surface tension is reduced for better penetrability, then ink penetration into recording member is improved, but nozzle stream bending occurs
Solution Approach 1:
The patent uses preliminary meniscus formation to counteract the harmful effects of reduced static surface tension. By creating a controlled meniscus shape before ejection, the system prepares the ink to maintain a straight nozzle stream despite low static surface tension. The pre-formed meniscus acts as a stabilizing structure that prevents stream bending during the subsequent ejection phase.
3Reliability
If dynamic surface tension is increased for discharge stability, then ejection stability is improved, but image quality degrades due to streaks
Solution Approach 1:
The patent segments the surface tension requirements into two phases: high dynamic surface tension during meniscus formation for stability, and controlled surface tension during ejection for quality. The two-signal drive method allows the system to benefit from high dynamic surface tension in the first phase while avoiding the streaking problem in the second phase, as the meniscus is already properly formed and positioned.
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 method enables stable ejection of ink with large surface tension differences, preventing nozzle stream bending and enhancing image quality by ensuring consistent droplet formation and penetration into recording media.
Implementation Method 1
a pressure generator that pressurizes the pressure chamber... ejecting the aqueous ink droplets by the pressure generated by the pressure generator
Implementation Method 2
the surface tension of the ink is different in different stages... the surface tension of the ink under the condition (when a new meniscus plane starts forming) regarded as a static condition
Data Source
AI summary
An inkjet recording method is performed using an inkjet recording device including a recording head provided with a nozzle, a pressure chamber, a pressure generator and a driving signal generator, the method satisfying the following requirements (1) and (2): (1) it is required to use aqueous ink having a dynamic surface tension larger by 10 mN/m or more than a static surface tension when the surface life measured at 25° C. by a maximum foaming pressure method is 15 ms and a dynamic surface tension larger by 5 mN/m or more than a static surface tension when the surface life measured by a maximum foaming pressure method is 1500 ms and (2) it is required that the signals have a drawing pulse in one print period and a meniscus of the aqueous ink is drawn into the nozzle in two stages by the drawing pulse.