Inkjet Print Head Mask Correction for Defective Nozzle Adaptability
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Solution Overview
Problem
Inkjet printing apparatuses face challenges in accurately correcting print mask data when ejection defective nozzles are identified, especially when the conveyance amount of the print medium is changed based on trailing edge detection, leading to inconsistent nozzle usage and potential image defects.
Innovation Solution
An inkjet printing apparatus with a conveyance unit, print head, detection unit, control unit, obtaining unit, and correction unit that divides mask patterns into groups based on defective nozzle information to adjust nozzle usage and conveyance amounts, ensuring accurate image printing across multiple pass operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the conveyance amount of the print medium is changed based on trailing edge detection timing, then the printing can be adapted to different print medium positions, but the nozzles in charge of printing each region vary depending on detection timing, causing inconsistent mask pattern correction
Solution Approach 1:
The patent divides the N mask patterns into multiple mask groups, where each mask group corresponds to a specific set of print scanning operations. This segmentation allows the system to apply different correction strategies to different portions of the printing process, ensuring that mask pattern correction remains consistent even when conveyance amount varies based on trailing edge detection timing.
Solution Approach 2:
The patent performs preliminary determination of nozzle usage ranges and conveyance amounts before executing the print scanning operations. By pre-determining these parameters based on the detected trailing edge position, the system ensures that the same nozzles are consistently assigned to specific regions throughout the printing process, enabling reliable mask pattern correction regardless of when the trailing edge is detected.
2Reliability
If mask patterns are corrected based on defective nozzle information, then image defects from defective nozzles can be reduced, but the correction may be inappropriate when nozzle usage ranges vary due to trailing edge detection timing
Solution Approach 1:
The patent determines the usage range of nozzles and conveyance amounts in advance, before performing mask pattern correction. This preliminary determination ensures that the correction unit has accurate information about which nozzles will be used for each region, allowing it to apply appropriate corrections to the mask patterns and avoid inappropriate corrections that would occur if nozzle usage varied during printing.
Solution Approach 2:
The patent uses detection information about the trailing edge position as feedback to adjust and determine the usage range of nozzles and conveyance amounts. This feedback mechanism ensures that the mask pattern correction is based on actual printing conditions, improving both the reliability of defect reduction and the precision of the correction by adapting to the specific printing scenario.
Data Source
AI summary
An inkjet printing apparatus is configured to print the image in N (N is an integer of four or more) print scanning operations of a print head for a unit region of the print medium by using N mask patterns used in the N print scanning operations. The inkjet printing apparatus includes: an obtaining unit configured to obtain defective nozzle information specifying a defective nozzle; and a correction unit configured to divide the N mask patterns into mask groups each corresponding to two or more print scanning operations and correct the mask patterns based on the defective nozzle information in each of the divided mask groups.