Laser Drying Device Ink Overlap Discoloration Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing drying devices in image forming apparatuses face issues with discoloring of printing parts when ink droplets overlap with pre-printed areas on the recording medium due to increased laser absorption, leading to unwanted color changes.

Innovation Solution

A controller adjusts the laser intensity to be lower than the set drying intensity for ink droplets overlapping with pre-printed areas on the recording medium by using a laser illumination intensity correction coefficient table, ensuring the laser absorption index of both the ink droplets and the printing parts are considered to prevent discoloration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If laser intensity is increased to improve drying efficiency of ink droplets, then drying speed is improved, but discoloration of pre-printed areas occurs due to increased laser absorption

Engineering Contradiction:

Improvedrying speedVSAvoiddiscoloration

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating laser intensity based on the specific region being processed. When ink droplets are detected on pre-printed areas, the controller reduces laser intensity specifically for those overlapping regions while maintaining normal intensity for other areas. This spatial differentiation of laser parameters prevents discoloration of pre-printed content while preserving drying efficiency for ink droplets.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting laser intensity based on the presence of ink droplets and pre-printed areas. The controller modifies the laser intensity parameter from the standard drying intensity to a reduced intensity specifically when overlapping regions are detected, thereby preventing excessive laser absorption and subsequent discoloration while maintaining effective drying elsewhere.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If laser intensity is reduced to prevent discoloration of pre-printed areas, then discoloration is suppressed, but drying efficiency of ink droplets decreases

Engineering Contradiction:

Improvediscoloration suppressionVSAvoiddrying efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the processing area into distinct regions: areas with ink droplets, pre-printed areas, and overlapping regions. The controller selectively applies different laser intensities to each segment - full intensity for drying ink droplets in non-overlapping areas, reduced intensity for pre-printed areas to prevent discoloration, and appropriately adjusted intensity for overlapping regions. This segmented approach maintains overall drying efficiency while protecting pre-printed content.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by applying reduced laser intensity only to the specific regions where pre-printed areas and ink droplets overlap, rather than reducing intensity across the entire processing area. This allows the laser to maintain full drying efficiency in regions without pre-printed content while applying protective reduced intensity only where necessary to prevent discoloration.

Inventive Principle:

Principle #16Partial or excessive action

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 discoloration of both the ink droplets and pre-printed areas by reducing the laser intensity for overlapping pixels, maintaining image quality and preventing unwanted color changes.

Implementation Method 1

a laser element configured to illuminate laser to the liquid droplet ejected on the image formation surface of the recording medium

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

the laser intensity becomes lower than a drying intensity set as an intensity for drying a liquid droplet

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9505237B2Drying device and image forming apparatus

Publication Date: 2016.11.29 FUJIFILM BUSINESS INNOVATION CORP

AI summary

There is provided a drying device. A controller is configured to control a laser intensity so that the laser intensity becomes lower than a drying intensity set as an intensity for drying a liquid droplet when a printing part printed in advance on a recording medium is included in an illumination range of a laser element on an image formation surface of the recording medium, the laser element configured to illuminate laser to the liquid droplet ejected on the image formation surface of the recording medium in accordance with an image.