Aqueous Varnish Stickiness Control in Image-Forming Devices

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Solution Overview

Problem

Image-forming devices face issues with blocking, where media coated with aqueous varnish adhere to each other, particularly in online-type and inline-type varnish application setups, due to high stickiness, which affects the adhesiveness and rub resistance of images.

Innovation Solution

The solution involves setting the stickiness evaluation value of the aqueous varnish to 0.24 or less by controlling drying and cooling treatment conditions, and adjusting the amount of powder sprayed, to prevent media adhesion and enhance adhesiveness between images and media.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If aqueous varnish is applied to media using online-type or inline-type varnish application, then the rub resistance and adhesiveness of images are improved, but the media adhere to each other causing blocking

Engineering Contradiction:
Improveadhesiveness between image and mediumVSAvoidblocking between media
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention controls the temperature parameter of the media after varnish application to be 101°C or higher, and adjusts the viscosity parameter of the aqueous varnish to 200 cP or lower, thereby reducing stickiness and preventing blocking while maintaining adhesiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary heating of the media to 101°C or higher before varnish application, and pre-adjusts the varnish viscosity to 200 cP or lower, so that when varnish is applied, the media are already in a state that prevents blocking while ensuring good adhesiveness

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If the temperature of media is kept lower than 101°C after treatment, then energy consumption is reduced, but blocking between loaded media occurs

Engineering Contradiction:
Improveenergy consumptionVSAvoidblocking between media
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The invention changes the temperature parameter to 101°C or higher and viscosity parameter to 200 cP or lower, which fundamentally alters the stickiness characteristics of the varnish-coated media, preventing blocking without requiring continuous high temperature maintenance that would consume excessive energy

Inventive Principle:
Principle #35Parameter changes

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 suppresses blocking between media loads and improves the adhesiveness between images and media, allowing for higher media loading and ink usage while maintaining image quality.

Implementation Method 1

a drying treatment portion that carries out a drying treatment on the paper on which the image is formed using the image-forming portion

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

after protective layers are formed on images, a heating treatment is carried out on the images and the protective layers, thereby improving adhesiveness between the images and the protective layers

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3257683B1Image-forming device and method for applying varnish
Publication Date: 2019.10.09 FUJIFILM CORP
  • EP3257683B1 patent drawingFigure 1
  • EP3257683B1 patent drawingFigure 2
  • EP3257683B1 patent drawingFigure 3

AI summary

An image-forming device includes a printing portion (40) that forms images on the media being transported using ink, a varnish application portion (60) that applies aqueous varnish to the media on which the images are formed, a treatment portion (50, 70) that performs a treatment on the media so that a stickiness evaluation value which is a stickiness evaluation value indicating a degree of stickiness of the aqueous varnish applied to the media when the media to which the aqueous varnish is applied are output from the varnish application portion and is derived using a damped vibration percentage of a pendulum caused to do pendulum motions from an arbitrary location of the media to which the aqueous varnish is applied as a pivot reaches 0.24 or less, and an accumulation portion (80) that accumulates the media to which the aqueous varnish is applied and on which the treatment is performed.