Ink Jet Line Head Ink Flow and Viscosity Control
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Solution Overview
Problem
Ink jet recording apparatuses with line heads face challenges in achieving high optical density and fixability of images while maintaining recoverability, as the line head's fixed structure hinders efficient ink recovery and leads to issues with ink thickening and sedimentation, affecting ejection and recovery processes.
Innovation Solution
An ink jet recording method using a line head with an ink having a pigment with an average particle diameter of 80 nm or more and dynamic surface tension of 55 mN/m or less, combined with an ink flow mechanism and viscosity reduction techniques, such as piezoelectric oscillation or thermal heating, to enhance ink flow and recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If ink is designed to improve optical density by leaving large amount of pigment on recording medium surface, then optical density is improved, but fixability deteriorates due to reduced ink permeation
Solution Approach 1:
The patent changes the physical parameters of pigment particles by controlling their size (0.01-1 μm range) and surface properties through surface treatment. This allows optimization of both optical density (by having sufficient pigment mass) and fixability (by enabling permeation through controlled particle characteristics and ink formulation with solvents and surfactants).
Solution Approach 2:
The patent uses composite ink formulations containing pigment particles combined with specific solvents and surfactants. This composite approach allows the ink to simultaneously carry sufficient pigment for high optical density while the solvent-surfactant matrix enables permeation for good fixability, resolving the trade-off between the two requirements.
2Productivity
If line head is used to improve recording speed, then productivity is improved, but recoverability deteriorates due to fixed structure preventing frequent recovering operations
Solution Approach 1:
The patent incorporates preliminary ejection mechanisms that perform recovery actions before main recording operations. The line head includes preliminary ejection nozzles positioned upstream that can clear pigment sedimentation and restore ink flow before the main recording nozzles are affected, enabling continuous high-speed recording without frequent full recovery operations.
Solution Approach 2:
The patent designs the line head with continuous ink circulation and preliminary ejection capabilities that maintain ink flow continuity. This allows the system to sustain high recording speeds by continuously preventing pigment deposition through ongoing preliminary ejection, rather than stopping for periodic recovery operations.
3Reliability
If ink flow rate is increased by pressurization to improve recovery, then recoverability is improved, but ink ejection performance deteriorates due to disrupted flow dynamics
Solution Approach 1:
The patent segments the ink ejection system into separate preliminary ejection nozzles and main recording nozzles. The preliminary nozzles handle high-pressure recovery operations to clear sedimentation, while the main nozzles maintain optimized low-pressure ejection for high-quality recording. This segmentation allows each subsystem to be optimized for its specific function without compromising the other.
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 improves the fixability and optical density of images while maintaining high recoverability of the ink jet recording apparatus, overcoming issues of ink thickening and sedimentation, and enabling efficient recovery operations.
Implementation Method 1
piezoelectric oscillation or thermal heating, to enhance ink flow and recovery
Implementation Method 2
piezoelectric oscillation or thermal heating, to enhance ink flow and recovery
Implementation Method 3
the ink has a dynamic surface tension of 55 mN/m or less at a lifetime of 10 milliseconds
Implementation Method 4
promptly infiltrate a liquid component of the ink, which has been applied to a recording medium, into the recording medium
Data Source
AI summary
To provide an ink jet recording method excellent in a fixability of an image, capable of recording an image excellent in optical density, and excellent in a recoverability, when it uses a recording apparatus having a line head. This method records an image by using an ink jet recording apparatus equipped with a line head having an ejection nozzle of a pigment-containing aqueous ink and a mechanism for recovering an ejection state of the aqueous ink from the nozzle and applying the ink to a recording medium. The pigment has an average particle diameter of 80 nm or more, the ink has a dynamic surface tension of 55 mN/m or less at a lifetime of 10 milliseconds, the recovery mechanism includes a mechanism for causing the ink in the nozzle to flow, and the viscosity of the ink in the nozzle is reduced.