Printing Apparatus Mask Selection for Special-Color Ink Drying

The patent applies different mask patterns to different regions of the overlap image based on local drying risk. The end part of the overlap image (farther from non-overlap image) receives a second mask pattern with fewer mask parts, while other regions receive a first mask pattern with more mask parts. This local differentiation allows maintaining print quality where needed while preserving ejection frequency in regions prone to drying.

The patent dynamically selects between first and second mask patterns based on the drying risk assessment of each nozzle. The controller determines drying risk for each nozzle and applies the appropriate mask pattern accordingly, making the masking strategy adaptive rather than static. This dynamic approach ensures optimal balance between print quality and preventing ink drying.

The patent implements local quality by applying different mask patterns to different regions. The second mask pattern with fewer mask parts is specifically applied to the end part of the overlap image where drying risk is highest, while the first mask pattern with more mask parts is applied to other regions where print quality is the primary concern. This spatial differentiation resolves the contradiction between print quality and ejection reliability.

The controller performs a preliminary assessment of drying risk for each nozzle before applying mask patterns. By obtaining information on drying risk in advance and selecting appropriate mask patterns based on this assessment, the system proactively prevents ejection failures due to drying while maintaining print quality where conditions permit.

The patent applies local quality by differentiating mask patterns based on position within the overlap image. The end part farther from the non-overlap image receives reduced masking (second mask pattern) to maintain ejection frequency and prevent drying, while other regions receive stronger masking (first mask pattern) to ensure print quality. This spatially varying approach resolves the contradiction between print quality and drying prevention.

The system performs preliminary drying risk assessment for each nozzle and proactively applies appropriate mask patterns before ejection failures occur. By obtaining drying risk information in advance and selecting mask patterns accordingly, the system prevents the harmful effect of ink drying while maintaining necessary print quality.