Segmented UV Irradiator for Gloss Coating Ink Leveling

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Solution Overview

Problem

Existing UV-curable inkjet apparatuses face challenges in performing gloss coating with clear ink, as the clear ink dissolves with color ink unless cured immediately after leveling, requiring complex and costly irradiator configurations to achieve continuous UV irradiation.

Innovation Solution

An ejecting apparatus with a control unit that moves in the main-scanning direction and an irradiating unit divided into blocks in the sub-scanning direction, where specific irradiating blocks are turned off to allow clear ink to level before curing, ensuring accurate gloss coating at a lower cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the clear ink is irradiated with UV rays immediately after ejection to prevent dissolution with color ink, then the dissolution problem is solved, but the gloss coating quality deteriorates because the ink cannot level properly

Engineering Contradiction:
Improveprevention of ink dissolutionVSAvoidgloss coating quality
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The irradiating unit is divided into multiple irradiating blocks arranged in the sub-scanning direction, allowing selective irradiation of different regions. This segmentation enables the system to irradiate color ink while allowing clear ink to level without immediate irradiation, resolving the contradiction between preventing dissolution and maintaining gloss quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the irradiating unit have different irradiation states - some blocks are turned on to irradiate color ink and prevent dissolution, while corresponding blocks for clear ink regions are turned off to allow leveling. This local differentiation resolves the contradiction by applying irradiation only where needed

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If two separate irradiators are used (one for color ink, one for clear ink) to achieve continuous UV irradiation, then the dissolution problem is solved, but the device complexity and cost increase

Engineering Contradiction:
Improveprevention of ink dissolutionVSAvoidirradiator configuration
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

A single irradiating unit is divided into multiple independently controllable irradiating blocks, replacing the need for two separate irradiators. This segmentation allows one irradiator to perform the functions of two irradiators by selectively turning on/off different blocks, reducing device complexity while maintaining the ability to prevent ink dissolution

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The single irradiating unit is designed to serve multiple functions - it can irradiate color ink to prevent dissolution, allow clear ink to level by turning off corresponding blocks, and provide continuous UV coverage. This multi-functionality eliminates the need for separate irradiators while maintaining effectiveness

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If one irradiator is partly turned off to achieve the effect of two irradiators, then the gloss coating quality is improved, but the device complexity increases due to scan-based control requirements

Engineering Contradiction:
Improvegloss coating qualityVSAvoidirradiator control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The irradiation control is made dynamic by enabling real-time on/off switching of individual irradiating blocks based on the scanning position and ink type being processed. This dynamic control allows the system to adapt irradiation patterns to current processing needs without requiring complex scan-based control systems

Inventive Principle:
Principle #15Dynamics

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

Enables accurate gloss coating while reducing costs by allowing clear ink to level without immediate UV exposure, ensuring a glossy finish without the need for complex or costly irradiator configurations.

Implementation Method 1

An irradiating unit 400R, 400L that emits ultraviolet rays is provided

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3691906B1Ejecting apparatus, image forming apparatus, curing method, and program
Publication Date: 2024.03.20 RICOH CO LTD
  • EP3691906B1 patent drawingFigure 1~2
  • EP3691906B1 patent drawingFigure 3
  • EP3691906B1 patent drawingFigure 4

AI summary

An ejecting apparatus includes an ejection control unit configured to cause a first ejecting unit among ejecting units (301) configured to move in a main-scanning direction, to eject a liquid; an irradiating unit (400) divided into a plurality of irradiating blocks (401) in a sub-scanning direction; an irradiation control unit configured to turn off an irradiating block corresponding to the first ejecting unit. A first distance (Y) between a downstream end of the first ejecting unit in the sub-scanning direction and an upstream end of an irradiating block is larger than a second distance (C) by which the irradiating block irradiates a recording medium outside from an end of an emission surface of the irradiator block in the sub-scanning direction. The irradiation control unit is configured to cure the liquid by causing the irradiating block positioned downstream of the turned- off irradiating block corresponding to the first ejecting unit, to emit the activation energy ray.