Positional-Deviation Correction for Image Density Variations
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Solution Overview
Problem
Image forming apparatuses face challenges in maintaining high image position accuracy due to changes in sheet shape caused by heat during the fixing process, leading to positional deviations in printed images.
Innovation Solution
A positional-deviation correcting device that includes a reading device and control circuitry to read marks and adjustment charts with different image densities, calculate correction values for image formation positions, and interpolate these values to correct image positioning accurately across various image densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single adjustment chart with fixed image density is used for positional deviation correction, then the correction process is simple, but the correction accuracy decreases when the actual image density differs from the adjustment chart density
Solution Approach 1:
The adjustment chart is segmented into multiple regions with different image densities (first through fourth densities). Each region contains correction marks that allow the reading device to calculate positional deviation specific to that density level. This segmentation enables the system to handle multiple density scenarios without requiring multiple separate adjustment charts, thus maintaining simplicity while improving accuracy.
Solution Approach 2:
The adjustment chart incorporates multiple image density parameters within a single structure. By varying the image density parameter across different regions (first density < second density < third density < fourth density), the system can correct positional deviations for images with different densities using a single adjustment chart, rather than requiring separate charts for each density level.
2Measurement precision
If multiple adjustment charts with different image densities are used to improve correction accuracy for various densities, then the correction accuracy improves, but the device complexity and operation complexity increase
Solution Approach 1:
Multiple adjustment charts with different image densities are merged into a single adjustment chart structure. The first through fourth adjustment charts are combined, with each containing correction marks at different positions and densities. This merging eliminates the need to manually select between multiple separate charts, reducing operational complexity while maintaining the ability to correct for various image densities.
Solution Approach 2:
The single adjustment chart serves multiple functions by incorporating correction capabilities for four different image density levels. The reading device can automatically identify which region of the adjustment chart corresponds to the actual image density and use the appropriate correction marks, making the adjustment chart universal for correcting positional deviations across a range of image densities.
3Productivity
If the reading device reads only correction marks without considering image density, then the reading process is fast and simple, but the correction accuracy decreases for images with varying densities
Solution Approach 1:
Different regions of the adjustment chart are assigned different image densities (first through fourth densities) to match different actual image conditions. The reading device reads correction marks from the specific region that corresponds to the actual image density, ensuring that the correction is locally optimized for the actual printing conditions while maintaining efficient automated reading.
Data Source
AI summary
A positional-deviation correcting device includes a reading device and control circuitry. The reading device reads recording media on which marks and each of adjustment charts having different image densities are formed in accordance with the image densities. The control circuitry acquires data on image formation positions of the marks on the recording media, based on a reading result of the marks; and corrects an image formation position of an image to be formed on a recording medium. The control circuitry calculates a correction value of the image formation position corresponding to an image density for each of the image densities corresponding to the adjustment charts on a one-on-one relationship, based on a reading result of the adjustment charts; interpolates correction values corresponding to the image densities on a one-on-one relationship; and calculates a correction value of the image formation position corresponding to another image density different from the image densities.