Inkjet Printer Shading Correction via Multi-Position Super-Resolution Imaging
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Solution Overview
Problem
High-resolution cameras are necessary for accurate shading correction in inkjet printing apparatuses, increasing manufacturing costs due to the need for precise determination of ink ejection differences from nozzles, which is not economically viable with increasing nozzle resolution.
Innovation Solution
An inkjet printing apparatus and method that uses a lower-resolution image capturing part to generate a super-resolution image by displacing the recording medium, allowing for the calculation of variable-density correction amounts for each nozzle, thereby reducing the need for high-resolution imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution camera is used to determine ink ejection differences from each nozzle, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent transitions from capturing a single high-resolution image to capturing multiple low-resolution images at different positions along the sub-scanning direction. By adding the temporal/dimensional dimension of multiple captures, the system achieves high measurement precision without requiring a high-resolution camera, thus resolving the contradiction between measurement accuracy and manufacturing cost.
Solution Approach 2:
The patent employs dynamic positioning where the recording medium is transported to different positions during the capturing process. The capturing part captures images at multiple discrete positions along the sub-scanning direction, and the controller synthesizes these dynamic captures into high-precision correction data, eliminating the need for expensive high-resolution imaging hardware.
2Manufacturing precision
If the nozzle density increases to achieve higher printing resolution, then printing quality is improved, but the requirement for high-resolution imaging equipment increases, worsening manufacturing cost
Solution Approach 1:
Instead of relying on the spatial resolution of the camera to distinguish individual nozzles, the patent uses the sub-scanning direction as an additional dimension. By capturing images at multiple positions along this dimension and synthesizing them, the system can resolve individual nozzle characteristics even when nozzles are densely packed beyond the camera's single-frame resolution capability.
Solution Approach 2:
The patent segments the imaging process into multiple discrete captures at different positions rather than attempting to capture all nozzle information in a single high-resolution frame. This segmentation allows the system to process and synthesize data from multiple lower-resolution captures, achieving high precision without requiring expensive high-resolution imaging equipment.
Data Source
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AI summary
First, shading charts are printed on a surface of a recording medium. Then, a plurality of captured images is acquired for a region of the same density of the shading charts printed on the recording medium. At this time, the amounts of displacement in the position of the recording medium in the main scanning direction, which is the direction of arrangement of nozzles, are also detected. Then, one super-resolution image with a higher resolution than the captured images is generated on the basis of the captured images and the amounts of displacement in the position of the recording medium in the main scanning direction. Thereafter, a variable-density correction amount is calculated for each of the nozzles on the basis of the generated super-resolution image.