Inkjet Printer Controller Banding Suppression
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Solution Overview
Problem
Banding occurs at the end portions of printed images due to instability in the print medium during inkjet printing, leading to poor image quality.
Innovation Solution
A controller for an inkjet printer determines optimal print processing based on the uniformity and noticeability of banding in the end regions by calculating specific values using weight information and color values, adjusting the print orientation and processing to minimize banding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If printing is performed at end portions of print medium where the print medium is held by only one holder, then printing can be completed across the entire medium, but banding occurs due to instability in the print medium
Solution Approach 1:
The patent applies local quality by differentiating print processing between two regions: end portion regions (where banding is likely to occur) and intermediate regions (where stability is better). The controller selectively applies different processing techniques - including image rotation and adjusted dot formation - specifically to the end portion regions, while using standard processing for intermediate regions. This localized approach resolves the contradiction by maintaining printing coverage while preventing banding only where necessary.
Solution Approach 2:
The patent changes physical parameters of the print medium orientation by rotating the image by 90 or 270 degrees before printing in end portion regions. This parameter change transforms the printing direction relative to the holder support, effectively converting unstable horizontal printing into stable vertical printing (or vice versa), thereby eliminating banding while maintaining complete printing coverage.
2Manufacturing precision
If image orientation is changed to avoid banding, then image quality improves, but processing complexity increases
Solution Approach 1:
The patent segments the print medium into two distinct regions: end portion regions and intermediate regions. By dividing the printing task this way, the system applies complex image rotation and specialized processing only to the problematic end portions, while leaving the majority (intermediate regions) to simple standard processing. This segmentation resolves the contradiction by limiting complexity to only where it is necessary for quality improvement.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and pre-rotating the image data before printing begins. The controller determines which regions require rotation and prepares the transformed image data in advance, so that during actual printing, the system simply executes the pre-planned orientation changes without real-time computation. This preliminary preparation reduces processing complexity during the printing operation itself.
Data Source
AI summary
A controller performs: acquiring target image data; calculating a particular value of a first end image by using the target image data, the first end image being an image to be printed in a first end region parallel to a first end of a print medium; determining print processing to be performed by using the particular value, including: when a particular condition is satisfied, determining first print processing as the print processing, the particular condition including a first condition that uniformity of the first end image is higher than or equal to a first standard; and when the particular condition is not satisfied, determining second print processing as the print processing, the first print processing being processing in which banding is less likely to occur in the first end image than the second print processing; and controlling the printer to print an image based on the target image data.