UV Light Source Focusing for Photo-Curable Ink Bleeding Control

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Solution Overview

Problem

Photo-curable ink used in ink jet printers experiences bleeding and reduced visibility due to its low viscosity, as it takes time for UV light emission to increase the viscosity after the ink lands on the printing surface, leading to delayed curing and poor image quality.

Innovation Solution

A charge control type ink jet printer is designed with a UV light source that emits UV light along the flying path of the ink droplets and focuses it onto the landing area, ensuring immediate curing and reducing bleeding, using a UV light source with a focal point adjusting mechanism and focusing mechanism to enhance light intensity and directionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If UV light emission is delayed until after ink landing, then the ink can maintain low viscosity for continuous discharge, but bleeding occurs and visibility is reduced due to delayed curing

Engineering Contradiction:
Improvecontinuous ink discharge capabilityVSAvoidimage visibility and bleeding control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by emitting UV light to the ink droplets during their flight path before they land on the printing surface. This preliminary curing action prevents bleeding upon impact while maintaining the low viscosity characteristic needed for continuous discharge. The UV light source is positioned to illuminate the flying path of the ink droplets, enabling curing to begin before the ink reaches the substrate.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If a large amount of monomer content is used to maintain low viscosity, then the ink can be discharged continuously, but the curing time increases and bleeding occurs

Engineering Contradiction:
Improvecontinuous discharge capabilityVSAvoidcuring time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs the curing action in advance during the ink droplet's flight path rather than waiting for the ink to land and then initiating curing. This preliminary UV illumination reduces the curing time needed after landing, preventing bleeding while maintaining continuous discharge capability through adequate monomer content.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If UV light is emitted along the flying path and focused onto the landing area, then immediate curing is achieved, but the device complexity increases due to focal point adjusting mechanism

Engineering Contradiction:
Improvecuring timing and location precisionVSAvoidUV light source configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by directing UV light specifically to the flying path and landing area of the ink droplets, rather than illuminating the entire printing surface. The focal point adjusting mechanism concentrates the UV light intensity precisely where needed - along the droplet trajectory and at the landing zone - achieving immediate curing with minimal additional device complexity.

Inventive Principle:
Principle #3Local 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 solution improves the visibility and reduces bleeding of the photo-curable ink by ensuring immediate curing upon landing, maintaining low solvent content and high image quality without the need for large emission devices.

Implementation Method 1

a photo-curable ink which is cross-linked by emitting UV light after recording

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

A charging electrode 2 applies predetermined charge to each of the ink droplets from a nozzle 1

Methodology Applied
Scientific EffectElectrostatic charge: Electrostatics

Implementation Method 3

The ink droplet is deflected in its trajectory by a deflection electrode 3

Methodology Applied
Scientific EffectElectrostatic deflection: Electrostatic Induction

Implementation Method 4

an ink conveyed to a nozzle by a pump is vibrated by an ultrasonic vibrator, and is then continuously pushed out to be very small droplets

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP2848408B1Charge control type ink jet printer and printing method
Publication Date: 2016.07.13 HITACHI IND EQUIP SYST CO LTD
  • EP2848408B1 patent drawingFigure 1~2
  • EP2848408B1 patent drawingFigure 3~4
  • EP2848408B1 patent drawingFigure 5

AI summary

The visibility of a printing object using a photocurable ink is improved. A charge control type ink jet printer includes a nozzle (1) which continuously forms ink droplets, a charging electrode (2) which charges each of the ink droplets, a deflection electrode (3) which deflects the charged ink droplet, and a print head (7) which discharges the deflected ink droplet to print the droplet onto a printed substrate. The print head has a UV light source(13). The UV light source (13) has a focusing member (17) which focuses UV light onto at least part of a flying path of the ink droplet between the print head (7) and the printed substrate (11) and onto a landed region of the printed substrate, and a light emission source (15).