Thermal Printer Gradation Control via Reflectance-Based Energy Mapping
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Solution Overview
Problem
Thermal printers face challenges in achieving high gradation reproducibility, particularly in the high density range, due to sharp changes in reflectance in low optical density and gradual changes in high optical density, leading to indiscernible gradations and reduced number of reproducible levels.
Innovation Solution
The thermal printer employs a configuration with micro control unit (MCU), random access memory (RAM), and heating elements, using a gradation table to set energy values based on dot area ratios, ensuring consistent differences between gradation levels and improving reflectance matching across the image range, allowing for smooth gradation reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If energy values are set based on optical density relationship, then optical density gradation is uniform, but reflectance gradation becomes indiscernible in high density range
Solution Approach 1:
The patent changes the parameter basis from optical density to reflectance when determining energy values for heating elements. By setting energy values based on reflectance relationships rather than optical density relationships, the system achieves uniform reflectance gradation across all density ranges, making gradations discernible even in high density areas where optical density-based methods fail.
2Productivity
If linear approximation is used for energy determination, then processing load is reduced, but gradation reproducibility deteriorates
Solution Approach 1:
The patent uses actual reflectance measurement data from printed images to create accurate energy value settings, replacing linear approximation methods. This approach maintains high processing efficiency while significantly improving gradation reproducibility by basing energy determination on empirical reflectance relationships rather than simplified linear models.
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 results in high-quality images with improved gradation reproducibility across the entire density range, ensuring clear gradations from low to high density with reduced data transfer times, enabling high-speed printing while maintaining image quality.
Implementation Method 1
multiple heating elements that generate heat corresponding to the amounts of energy applied
Implementation Method 2
thermal printer configured to apply energy to heating elements in a thermal head in accordance with gradation levels of image data
Data Source
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AI summary
A thermal printer includes heating elements that generate heat according to amounts of applied energy, an energy applier that applies energy to the heating elements, a memory that stores a gradation table where energy levels to be applied to the heating elements are set for gradation levels based on a relationship between dot area ratios of an image and the amounts of energy applied to the heating elements, and a controller that transfers control data multiple times to the energy applier based on the gradation table to control the amounts of energy to be applied by the energy applier to the heating elements, each of the control data corresponding to different amounts of energy.