Ink Jet Recording Apparatus Pigment Aggregation Control
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Solution Overview
Problem
Ink jet recording methods face challenges with degraded image quality due to pigment aggregation and increased pigment concentration in the nozzle over extended use, leading to reduced intermittent ejection stability, especially with larger main tank capacities.
Innovation Solution
The method involves a specific capacity ratio of 3.0 to 50.0 times between the main tank and sub tank, using a water-soluble organic solvent with a relative dielectric constant of 10.0 to 30.0, and adjusting the ink viscosity by heating to maintain pigment dispersion and reduce pigment aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the main tank capacity is increased to increase productivity, then the number of recorded documents increases, but pigment aggregation occurs and image quality degrades over extended use
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by specifying a water-soluble organic solvent with a relative dielectric constant of 10.0 or more but less than 30.0 at 25°C, and controlling the solvent content to 2.0 or more but less than 10.0 times the pigment content. This parameter optimization prevents pigment aggregation even during extended recording operations with large main tank capacity, thereby maintaining image quality while increasing productivity.
2Reliability
If a water-soluble organic solvent is added to improve intermittent ejection stability, then ejection stability improves, but pigment aggregation occurs during extended recording operations
Solution Approach 1:
The patent optimizes the dielectric constant parameter of the water-soluble organic solvent to a specific range (10.0 or more but less than 30.0 at 25°C) and controls the solvent-to-pigment content ratio (2.0 or more but less than 10.0 times). This balanced parameter selection simultaneously maintains intermittent ejection stability and prevents pigment aggregation during extended recording operations.
Solution Approach 2:
The water-soluble organic solvent acts as a protective medium surrounding pigment particles, creating a flexible chemical environment that maintains pigment dispersion stability. The specific dielectric constant range ensures the solvent provides adequate solvation without causing excessive pigment aggregation, thus maintaining both ejection stability and pigment dispersion during extended use.
3Productivity
If the ink storage amount in the main tank is increased, then productivity increases, but pigment concentration in the nozzle increases leading to degraded image quality
Solution Approach 1:
The patent changes the ink composition parameters by controlling the water-soluble organic solvent content to be 2.0 or more but less than 10.0 times the pigment content, and selecting solvents with specific dielectric constants. This composition optimization prevents pigment concentration increase in the nozzle during extended recording operations with large main tank capacity, thereby maintaining both productivity and image quality.
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 effectively reduces pigment aggregation and maintains high intermittent ejection stability by diffusing pigment deep into the nozzle, thereby improving image quality and extending the service life of the recording apparatus.
Implementation Method 1
diffusing pigment deep into the nozzle
Implementation Method 2
maintains high intermittent ejection stability by diffusing pigment deep into the nozzle
Implementation Method 3
adjusting the ink viscosity by heating
Implementation Method 4
the ratio of the viscosity of the aqueous ink in the recording head (ηB) to the viscosity of the aqueous ink at a temperature of 25° C. (ηA) is 0.8 or less
Data Source
AI summary
An ink jet recording method comprising ejecting an ink from a recording head to record an image on a recording medium using an ink jet recording apparatus. The ink jet recording apparatus includes a main tank, a sub tank, and a recording head. The ratio of the maximum ink storage amount of the main tank to the maximum ink storage amount of the sub tank is 3.0 or more to 50.0 or less. The ink contains a pigment and a particular water-soluble organic solvent. The ratio of the water-soluble organic solvent content to the pigment content is 2.0 or more to 10.0 or less. The ink has a temperature at which the ratio of the viscosity of the ink in the recording head to the viscosity of the ink at a temperature of 25° C. is 0.8 or less.