Thermal Printer Gradation Table Reflectance Control
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Solution Overview
Problem
Existing 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 indiscernible gradations, which limits the number of reproducible gradation levels.
Innovation Solution
A thermal printer with heating elements grouped into printing blocks, controlled by a microcontroller using a gradation table that sets energy values based on the relationship between reflectances and applied energy, ensuring consistent energy application across gradation levels to maintain smooth gradations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If energy values are set based on optical density relationship, then processing load is reduced, but gradation reproducibility deteriorates in high density range
Solution Approach 1:
The patent changes the parameter basis from optical density to reflectance for setting energy values in the gradation table. This parameter change allows energy values to be determined based on the reflectance-energy relationship, which maintains constant reflectance differences between gradation levels, thereby improving gradation reproducibility while still using a pre-calculated table to reduce processing load during actual printing operations.
2Ease of operation
If energy values are set to achieve constant optical density intervals, then optical density control is simplified, but reflectance uniformity deteriorates
Solution Approach 1:
The patent changes the control parameter from optical density to reflectance. By setting energy values based on the reflectance-energy relationship rather than optical density-energy relationship, the system achieves constant reflectance differences between gradation levels. This parameter change directly improves reflectance uniformity while maintaining ease of operation through the use of pre-calculated gradation tables.
3Productivity
If linear approximation is used for energy determination, then processing speed increases, but gradation quality deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating the correct energy values for each gradation level based on the reflectance-energy relationship and storing them in a gradation table during system initialization or calibration. This allows the printer to directly lookup and use pre-determined energy values during printing operations, achieving both high processing speed and high gradation quality without requiring complex real-time calculations.
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
The solution enhances gradation reproducibility by ensuring consistent reflectance across gradation levels, improving the quality of printed images with clear gradations in both low and high density ranges, and allows for high-speed printing by reducing data transfer.
Implementation Method 1
heating elements each of which generates heat according to an amount of energy applied thereto
Data Source
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AI summary
A thermal printer includes heating elements each of which generates heat according to an amount of energy applied thereto, an energy applier that applies energy to each of the heating elements, a memory that stores a gradation table where energy values are set for gradation levels based on a relationship between reflectances of a printed image and amounts of energy applied to the heating elements, and a controller that transfers control data corresponding to gradation levels of image data to the energy applier based on the gradation table to control the amounts of energy to be applied by the energy applier to each of the heating elements.