Thermal Transfer Printer Density Correction via Single-Tone Test
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Solution Overview
Problem
Thermal transfer printers face challenges in accurately correcting density irregularities due to mechanical and thermal variations in the thermal head, which can be exacerbated by sheet meandering, requiring complex and time-consuming correction processes.
Innovation Solution
A thermal transfer printer system that includes a thermal head with a storage unit for correction data and a control unit to adjust energy applied to heating elements based on a correspondence between heating element positions and image densities, using a test image of single tone to simplify the correction process and account for varying print speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test image with belt-like patterns of multiple tones is used for correction, then the accuracy of density measurement is improved, but the complexity of the correction process and time required increase significantly
Solution Approach 1:
The invention extracts only the necessary single-tone test image for correction, removing the unnecessary multiple-tone belt-like patterns. This simplifies the correction process while maintaining the ability to measure density accurately, as single-tone images provide sufficient information for creating correction data without the complexity of multiple tones.
Solution Approach 2:
The invention focuses correction on specific local characteristics by using single-tone test images that target particular density irregularities. Instead of attempting to correct all tone variations simultaneously with complex multi-tone patterns, the system applies localized correction based on single-tone measurements, making the process more efficient and manageable.
2Quantity of substance
If a test image with belt-like patterns of multiple tones is used for correction, then the comprehensiveness of density coverage is improved, but the time required for correction work increases
Solution Approach 1:
The invention performs preliminary correction using single-tone test images that capture the essential density characteristics needed for correction. By establishing correction data from simple single-tone measurements beforehand, the system avoids the time-consuming process of using complex multi-tone patterns while still achieving comprehensive density coverage through subsequent application of the correction data to actual images.
3Manufacturing precision
If correction is performed using traditional methods, then density irregularities can be addressed, but sheet meandering causes positional relationship changes that reduce correction accuracy
Solution Approach 1:
The invention changes the approach from position-dependent correction to parameter-based correction by using single-tone density measurements. This allows the system to create correction data that is independent of precise positional relationships, making the correction more reliable even when sheet meandering occurs during printing, as the correction parameters are derived from overall density characteristics rather than position-specific measurements.
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 solution allows for more accurate and efficient correction of density irregularities, reducing the impact of sheet meandering and thermal/mechanical variations, thereby improving print quality and simplifying the correction process.
Implementation Method 1
a thermal head arranged with as many heating elements (heat generating resistors) as a number corresponding to the number of pixels in one line in the main scanning direction, and causes the heating elements to generate heat in accordance with image data
Data Source
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AI summary
Irregularities in the density that can occur in printed images of a thermal transfer printer due to mechanical variations or variations in thermal characteristics in the thermal head are more easily and accurately corrected as compared to cases not having the features of the disclosed invention. The thermal transfer printer includes a thermal head including heating elements and causing the heating elements to generate heat and transfer ink onto a sheet to print an image on the sheet, a storage unit for storing a first correspondence between a heating element in the thermal head and a correction amount of energy applied to the heating element and a second correspondence between a density of an image to be printed and an adjustment coefficient of the correction amount, and a control unit for correcting energy applied to each heating element by an amount obtained by multiplying the correction amount for the heating element obtained from the first correspondence by the adjustment coefficient obtained from the second correspondence according to a density of an image to be newly printed. The first correspondence is generated from a density distribution of a test image printed based on image data of a single tone.