Humidity-Controlled Transport Module for High-Speed Ink Absorption

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Solution Overview

Problem

High-speed printing systems produce printed matter with inferior drying robustness due to limited ink absorption into porous substrates, primarily caused by evaporation of solvents and viscosity increase in ink compositions.

Innovation Solution

A printing system with a transport module that controls relative humidity between 50% and 100% and temperature between 40°C and 80°C to prevent evaporation, allowing for extended ink absorption into the substrate before drying, using a transport path length calculated to optimize absorption time, and employing substrates and inks with high absorption characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If printing speed is increased to >200-400 A4 images per minute, then productivity is improved, but ink absorption into the substrate is limited resulting in inferior drying robustness

Engineering Contradiction:

Improveprinting speedVSAvoiddrying robustness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The transport module creates a humid environment (RH≥50%) before the substrate enters the drying/fixation module, preliminarily preventing ink evaporation and maintaining low viscosity to promote absorption. This preliminary action ensures the ink is ready for optimal absorption before the high-speed drying process begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the environmental parameters (relative humidity and temperature) in the transport module to optimize ink absorption. By maintaining RH≥50% and controlled temperature (40-80°C), the ink viscosity is kept low, enabling effective absorption even at high printing speeds where residence time is limited.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the substrate moves quickly through the transport module at high printing speeds, then productivity is improved, but the residence time for ink absorption is reduced limiting absorption efficiency

Engineering Contradiction:

Improveprinting speedVSAvoidresidence time for absorption

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

Instead of increasing residence time by slowing transport, the invention changes the environmental parameters (RH≥50%, temperature 40-80°C) to accelerate the absorption rate. This allows sufficient absorption to occur within the short residence time at high printing speeds by creating optimal conditions for rapid ink uptake.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The humid environment in the transport module preliminarily counteracts the harmful effect of rapid evaporation that would normally occur at high speeds. By pre-establishing conditions that favor absorption over evaporation, the system compensates for the reduced residence time without reducing printing speed.

Inventive Principle:

Principle #9Preliminary anti-action

3Loss of substance

If evaporation of solvents is allowed to occur during transport, then the ink composition viscosity increases, but this limits further absorption of ink into the substrate

Engineering Contradiction:

Improvesolvent evaporationVSAvoidink absorption

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The transport module creates a humid, inert-like environment (RH≥50%) that prevents harmful evaporation of ink solvents. This controlled atmosphere acts as a protective medium that maintains ink composition stability and low viscosity, enabling continuous absorption into the substrate without the adverse effects of premature evaporation.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The invention converts the potentially harmful effect of evaporation into a beneficial process by controlling humidity levels. The controlled evaporation in a humid environment allows moderate viscosity increase that can actually promote absorption in certain ink-substrate systems, while preventing the excessive viscosity increase that would block absorption.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 drying robustness by reducing residual ink on the surface, promoting ink absorption and maintaining optimal viscosity, resulting in improved print quality and robustness at high printing speeds.

Implementation Method 1

evaporation of solvents (including water) present in the ink composition and absorption of ink constituents in the print substrate, all within 100-1000 ms

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

absorption of ink constituents in the print substrate

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

absorption characteristics

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS10603905B2Method of printing

Publication Date: 2020.03.31 CANON PRODN PRINTING HLDG BV

AI summary

A printing system and method for improving ink absorption in a print substrate by preventing evaporation includes a conditioned transport module arranged for transporting a printed print substrate from a (conditioned) image formation module to a drying/fixation module. The transport module includes a control system configured for controlling the relative humidity inside the transport module to at least 50%.