Thermal Transfer Printing Ink Content Stabilization

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Solution Overview

Problem

Variations in ink content and environmental conditions lead to inconsistent image quality in thermal transfer printing, as the same printing energy applied to ink ribbons with different ink amounts or used in different environments result in varying image densities.

Innovation Solution

A thermal transfer printing apparatus and method that includes a sensor to measure the ink ribbon's light transmission intensity through colored layers and a protection layer, adjusting the thermal head's energy application based on these measurements to stabilize image quality by selecting the appropriate energy table from a storage unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the same printing energy is applied by a thermal head to ink ribbons with different ink amounts, then the printing process is simple and fast, but the image density and quality vary

Engineering Contradiction:
Improveprinting speedVSAvoidimage density consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The sensor measures the ink content of the ink ribbon before the thermal printing process begins. This preliminary measurement allows the system to determine the appropriate printing energy in advance, ensuring consistent image density regardless of variations in ink ribbon composition. The measurement is performed by irradiating the ink ribbon with light and detecting the transmitted light intensity through the colored layers.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the printing energy parameter based on the measured ink content. When the ink content is detected to be higher or lower than standard, the thermal head modifies its energy output accordingly to compensate for the variation, thereby maintaining uniform image density across different ink ribbons.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If printing is performed without considering environmental conditions, then the printing process is simple, but image quality varies due to temperature and humidity differences

Engineering Contradiction:
Improveprinting process complexityVSAvoidimage quality consistency
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The sensor provides feedback about the ink ribbon's actual ink content, which may be influenced by environmental storage conditions such as temperature and humidity. This feedback loop enables the system to adapt to environmental variations by adjusting printing energy based on the measured ink transmission characteristics, thereby maintaining consistent image quality despite changes in storage environment.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If a sensor measures light transmission through the ink ribbon to detect ink content, then image quality can be stabilized, but the device complexity increases

Engineering Contradiction:
Improveimage quality stabilityVSAvoidapparatus structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A light sensor is introduced as an intermediary device between the ink ribbon and the thermal printing process. The sensor measures the light transmission characteristics of the ink ribbon's colored layers to detect ink content variations. This intermediary measurement enables automatic compensation without requiring complex manual intervention or sophisticated control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures consistent image quality by accurately measuring ink content and environmental factors, allowing for precise energy control to match the ink ribbon's characteristics, thereby stabilizing the printed image quality.

Implementation Method 1

a sensor that measures an ink content of the ink ribbon

Methodology Applied
Scientific EffectLight transmission: Absorption (EM radiation)

Implementation Method 2

transfers ink of an ink ribbon onto printing paper in a pattern corresponding to an image by applying heat from a thermal head to the ink ribbon

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3647061B1Thermal transfer printing apparatus and thermal transfer printing method
Publication Date: 2022.12.07 DAI NIPPON PRINTING CO LTD
  • EP3647061B1 patent drawingFigure 1~2
  • EP3647061B1 patent drawingFigure 3
  • EP3647061B1 patent drawingFigure 4

AI summary

To stabilize image quality of a printed image. A thermal transfer printing apparatus according to the present invention includes a thermal head 1 and a platen roll 2 and forms an image on printing paper 7 by causing the thermal head 1 to heat an ink ribbon 5 including a plurality of consecutive ink layers 50, each of which includes sequential panels of a yellow layer 51, a magenta layer 52, and a cyan layer 53 and thereby transfer ink while transporting, between the thermal head 1 and the platen roll 2, the ink ribbon 5 and the printing paper 7 that are superimposed on each other. The thermal transfer printing apparatus includes a sensor 20 that detects ink content of the ink layers 50 and a controller 10 that controls energy applied to the thermal head 1 during image formation on a basis of a result of the detection of the sensor 20.