Thermal Response Correction for Multicolor Printing

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Solution Overview

Problem

Conventional thermal printers face challenges in accurately reproducing sharp density gradients and maintaining thermal history control when printing multiple colors in a single pass, leading to distortions in density and color due to heat retention and inter-color interactions.

Innovation Solution

The method involves dividing each pixel-printing interval into segments of unequal duration for each color, using distinct energy computation functions and thermal model parameters to adjust energy input based on previous color energies and desired densities, ensuring precise thermal control across multiple color-forming layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single thermal print head prints multiple colors in a single pass, then productivity is improved, but manufacturing precision deteriorates due to thermal history effects and heat retention

Engineering Contradiction:
Improveprinting speedVSAvoiddensity gradient accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The printing process is divided into separate segments for different colors, with each color receiving dedicated time intervals and energy computation functions. This segmentation allows independent thermal control for each color layer, preventing thermal interference while maintaining high-speed single-pass printing capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system pre-calculates thermal history effects and compensates for heat retention before actual printing occurs. By predicting temperature variations and adjusting energy input in advance, the system maintains density accuracy despite the thermal accumulation inherent in rapid multi-color printing

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If energy input is increased to maintain density, then manufacturing precision is improved, but loss of energy increases due to thermal history accumulation

Engineering Contradiction:
Improvedensity control accuracyVSAvoidthermal energy waste
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The system implements a feedback mechanism that continuously monitors thermal history and adjusts energy input accordingly. By measuring the cumulative thermal effect from previous colors and printing operations, the system dynamically compensates energy distribution to maintain precise density control while minimizing unnecessary energy consumption

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes energy computation parameters based on thermal history state. Different energy computation functions are applied to different colors and time intervals, optimizing energy input to achieve required density while accounting for thermal accumulation and preventing energy waste

Inventive Principle:
Principle #35Parameter changes

3Productivity

If printing time is reduced for single-pass multi-color, then productivity is improved, but manufacturing precision deteriorates due to insufficient thermal control

Engineering Contradiction:
Improveprinting throughputVSAvoidcolor accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system employs dynamic energy computation that adapts to real-time thermal conditions during the printing process. By continuously adjusting energy input based on thermal history and color-specific requirements, the system maintains high printing speed while ensuring accurate color reproduction without requiring extended printing time

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

This approach enhances the quality of thermal history control, reducing density drift and color distortions by accurately managing thermal history and energy distribution across multiple colors, resulting in improved image sharpness and color accuracy.

Implementation Method 1

A thermal print head heating element is activated by supplying it with energy. Supplying energy to the print head element raises the temperature of the print head element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2296902B1Thermal response correction system for multicolor printing
Publication Date: 2017.08.16 ZINK IMAGING LLC
  • EP2296902B1 patent drawingFigure 1
  • EP2296902B1 patent drawingFigure 2
  • EP2296902B1 patent drawingFigure 3

AI summary

Thermal history control is performed in a thermal printer in which a single thermal print head prints sequentially on multiple color-forming layers in a single pass. Each pixel-printing interval may be divided into segments, each of which may be used to print a different color. The manner in which the input energy to be provided to each print head element is selected may be varied for each segment. Different energy computation functions may be used to compute the energy to provide to the print head in each of the segments based on the predicted print head element temperature at the beginning of the segment, the color to be printed, and the energy that was supplied when printing other colors during the time period between the beginning of the segment of the current pixel-printing interval and the end of the equivalent segment of the previous pixel-printing interval.