Image Processing Apparatus Reducing Ink Streaks at Band Joints
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Solution Overview
Problem
Inkjet printers experience high-density streaks at the joints between adjacent bands printed through different main scans due to ink overlap, which existing halftone processes fail to adequately address.
Innovation Solution
An image processing apparatus and method that generates corrected print data by dividing edge part data into block data, determining an ink amount index value, and adjusting the size information of dot data within each block to reduce ink usage, thereby minimizing streaks at the joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If band-by-band image print operation is repeated to print images wider than a single band, then the printing area is expanded, but high-density streaks are generated at the joint between adjacent bands
Solution Approach 1:
The patent applies local quality by differentiating the processing of edge region dot data from regular region dot data. Specifically, the edge part data is divided into multiple block data, and the size information of dot data in each block is independently adjusted based on calculated index values, while regular region dot data remains unchanged. This localized adjustment reduces ink usage at joints without affecting overall print quality.
Solution Approach 2:
The patent segments the edge part data into multiple block data units along the main scanning direction. Each block contains a specific number of dot data (e.g., 10 dots), and the size information of dots in each block is independently modified. This segmentation allows precise control of ink usage in different regions of the joint area.
2Object-generated harmful factors
If the number of dots is counted and pixels are reduced in accordance with dot count value, then streaks at joints are reduced, but the complexity of the correction process increases
Solution Approach 1:
The patent changes the parameter of dot size information in the print data. By calculating an index value based on the number of dots in each block and then adjusting the size information of dot data according to this index, the system modifies a key parameter to control ink usage. This approach is more systematic and easier to implement than complex pixel-level correction based on dot counting.
3Loss of substance
If the size information of dot data in edge regions is reduced, then ink usage at joints is decreased, but the image quality in edge regions may deteriorate
Solution Approach 1:
The patent applies partial action by selectively reducing the size information of only the dot data located in edge regions (specifically in block data derived from edge part data), while leaving the size information of dot data in regular regions unchanged. This partial modification reduces ink usage at problematic joint areas without compromising the overall image quality.
Solution Approach 2:
The patent introduces dynamic adjustment of dot size information based on calculated index values. The size information is not fixed but is dynamically modified according to the specific characteristics of each block (number of dots, position, etc.). This dynamic approach allows optimization of ink usage while maintaining image quality through data-driven decisions.
Data Source
AI summary
In an image processing apparatus, the generating unit generates print data indicating whether a dot having one of a plurality of sizes is formed or not, by performing a halftone process on original image data. The correcting unit generates corrected print data by correcting the print data. The dividing unit divides the edge part data of the print data into a plurality of block data. The index value determining unit determines, for each block data, an index value relating to an amount of ink to be used based on the plurality of dot data included in the each block data. The changing unit changes, for each block data, the size information of at least one dot data among the plurality of dot data included in the each block data based on the index value such that the amount of ink to be used becomes reduced.