Printing Apparatus Color Shift Correction via Pattern Overlap
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Solution Overview
Problem
Color shift phenomena occur in printing due to differences in expansion/contraction extents of color inks, particularly noticeable in indirect printing schemes, where high gradation areas and low specific heat transfer media exacerbate image quality degradation, and existing correction techniques do not effectively address these issues.
Innovation Solution
A printing apparatus that combines printing data with pattern data to correct the printing start position of color inks, using a storage/generation section to generate pattern data, a combining section to overlap printing images, and a correction section to adjust the printing start position based on input shift information, thereby minimizing color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If indirect printing scheme is used with low specific heat transfer medium, then printing speed and efficiency are improved, but color shift occurs due to differential expansion/contraction of color inks
Solution Approach 1:
The patent applies preliminary action by printing correction patterns (concentration correction pattern and color shift correction pattern) on the intermediate transfer belt before actual image printing. These correction patterns are printed in advance to measure and compensate for color shift that will occur during subsequent printing operations, allowing the system to pre-calculate and apply correction values to maintain color alignment precision while using the efficient indirect printing scheme
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting printing parameters based on measured color shift. The system measures the actual color shift using the correction patterns and modifies printing parameters (such as printing start positions and ink concentrations) accordingly. This allows the system to adapt to differential expansion/contraction of color inks on the low specific heat transfer medium, maintaining color alignment precision while preserving the productivity benefits of indirect printing
2Area of stationary object
If high gradation ink is used in large area, then image coverage and visual quality are improved, but color shift increases due to greater expansion/contraction
Solution Approach 1:
The patent applies local quality by implementing position-dependent correction. Different regions of the printing medium may experience different degrees of expansion/contraction, so the system applies localized correction values to different areas. The concentration correction pattern and color shift correction pattern allow measurement and compensation of color shift specific to each region, enabling high gradation ink to be used in large areas while maintaining color alignment precision through area-specific adjustments
Solution Approach 2:
The system dynamically changes printing parameters based on the specific printing conditions including the area and gradation of ink application. When large area high gradation printing is detected, the system adjusts printing parameters such as ink concentration, printing speed, and start positions to compensate for the increased expansion/contraction effects, thereby maintaining color alignment precision while achieving full image coverage
3Measurement precision
If correction patterns are printed on intermediate transfer belt, then color shift measurement capability is improved, but printing time increases due to additional printing steps
Solution Approach 1:
The patent merges the correction pattern printing with the normal printing process. The concentration correction pattern and color shift correction pattern are printed on the intermediate transfer belt in the same printing pass as the actual image data, rather than requiring separate dedicated correction printing steps. This integration allows the system to maintain high measurement precision while minimizing additional printing time, as the correction patterns are generated and printed concurrently with regular printing operations
Solution Approach 2:
The system applies partial correction action by selectively applying correction only where needed. Rather than correcting all printing operations uniformly, the system measures color shift using the correction patterns and applies corrections only to the extent necessary based on actual measured deviations. This allows the system to achieve accurate color shift measurement and correction while minimizing the time overhead, applying full correction only when color shift exceeds acceptable thresholds
Data Source
AI summary
To correct a color shift caused by printing data, a printing apparatus includes an image formation section that prints on a transfer film using color inks according to printing data, and a control section which stores or generates pattern data of a pattern having respective colors of the inks, and combines the printing data and the pattern data so that a printing image of the pattern data overlaps a part of a printing image of the printing data. The control section corrects a printing start position on the transfer film with the image formation section of at least one color ink among printing images to print respectively with the color inks, according to input first information concerning a shift in respective colors of the inks constituting the pattern occurring in forming an image on the transfer film in the image formation section according to combined printing data subjected to combining.