Ink Jet Recording Head Degassing Efficiency
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Solution Overview
Problem
Ink jet recording methods face challenges with decreased degassing efficiency over time, particularly when using a line-type recording head with ink circulation systems, due to air bubbles and pigment aggregation, which affects ejection reliability and recording speed.
Innovation Solution
An ink composition containing a pigment dispersed by an anionic group, a resin particle, and a water-soluble organic solvent with a relative dielectric constant of 34.0 or less is used, which helps maintain stable dispersion and prevents thickening, thereby enhancing degassing efficiency by facilitating air bubble escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink circulation is performed to improve ejection recoverability, then ink supply stability is improved, but dissolved air accumulates and causes ejection irregularities
Solution Approach 1:
The patent extracts dissolved air from the circulating ink through a degassing unit equipped with a gas permeable membrane. The ink flows through the membrane under reduced pressure, allowing dissolved air to be removed while retaining the ink circulation system's benefits for ejection recoverability.
Solution Approach 2:
A gas permeable membrane is introduced as an intermediary between the circulating ink and the external environment. This membrane selectively allows air molecules to pass through while preventing ink leakage, enabling continuous degassing during ink circulation.
2Reliability
If degassing is performed while circulating ink, then ejection recoverability is improved, but degassing efficiency decreases after long period recording
Solution Approach 1:
The patent applies preliminary action by adding a surfactant to the ink before circulation begins. This surfactant pre-conditioning prevents pigment aggregation and maintains stable ink properties, ensuring consistent degassing efficiency throughout extended recording operations.
Solution Approach 2:
The patent changes the chemical composition parameters of the ink by incorporating specific surfactants that maintain ink stability during prolonged circulation and degassing operations, preventing the efficiency degradation that occurs with standard ink formulations.
3Productivity
If line-type recording head is used to increase recording speed, then productivity is improved, but recovery operation becomes difficult during pause periods
Solution Approach 1:
The patent implements continuous ink circulation through the line-type recording head, ensuring that ink continuously flows through the ejection nozzles even during pause periods between recording operations. This continuous circulation prevents ink stagnation and sticking, maintaining ejection reliability without requiring separate recovery operations.
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 proposed ink composition effectively suppresses the decrease in degassing efficiency over time, ensuring consistent ejection reliability and improved recording performance by preventing pigment aggregation and air bubble hindrance at the gas-liquid interface.
Implementation Method 1
a unit for degassing the ink circulating in the ink circulation system
Data Source
AI summary
Provided is an ink jet recording method by which the decrease of degassing efficiency is suppressed even after images are recorded for a long period of time in a case where the degassing is performed while circulating an ink in an ink circulation system. An ink jet recording method recording an image on a recording medium by ejecting an ink from a recording head by using an ink jet recording apparatus equipped with an ink storage portion for storing the ink, the recording head for ejecting the ink, a unit for circulating the ink in an ink circulation system arranged between the ink storage portion and the recording head and a unit for degassing the ink circulating in the ink circulation system, the ink being an aqueous ink containing a pigment dispersed by an action of an anionic group, a resin particle and a specific water-soluble organic solvent.