Printing Apparatus Nozzle Overlap Density Control
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Solution Overview
Problem
Existing printing technologies face challenges in eliminating density unevenness caused by the overlapping portions of nozzle rows that eject the same liquid, leading to issues like black streaks and white streaks in printing results.
Innovation Solution
A printing apparatus with a control unit that manages the ejection of liquid from a printing head with overlapping nozzle rows. The control unit prints a test pattern to determine the use ranges of the nozzles in the overlapping portion, adjusting the number of nozzle pairs used for printing to minimize density differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data shifting is performed in units of nozzle rows to eliminate density unevenness due to overlapping portions, then density unevenness is reduced, but deviation between colors is easily caused again
Solution Approach 1:
The patent divides the nozzle rows into multiple groups and performs data shifting at the group level rather than individual nozzle row level. This segmentation allows for coarser adjustment that eliminates density unevenness while maintaining color alignment, as the shifting is applied to larger segments that encompass multiple nozzle rows working together.
Solution Approach 2:
The patent applies different data shifting amounts to different nozzle row groups based on their specific characteristics and positions. By determining appropriate shifting amounts for each group locally rather than applying a uniform shift globally, the system can correct density unevenness in each overlapping region while preserving overall color accuracy across the entire printing system.
2Productivity
If the number of nozzle pairs used for printing is increased to improve printing speed, then productivity is improved, but density unevenness in overlapping portions becomes more noticeable
Solution Approach 1:
The patent dynamically adjusts the number of nozzle pairs used for printing based on real-time detection of density unevenness. The system can flexibly switch between using more nozzle pairs for speed and fewer nozzle pairs for quality, adapting to different printing conditions and requirements without being constrained by a fixed configuration.
Solution Approach 2:
The patent changes the operational parameters of the printing system by adjusting which specific nozzle pairs are activated and how many are used. By selectively controlling the participation of nozzle pairs in the overlapping portions, the system can optimize the balance between printing speed and density uniformity according to the specific printing task and detected conditions.
Data Source
AI summary
A printing head includes an overlapping portion in which a first nozzle row in which a plurality of first nozzles and a second nozzle row in which a plurality of second nozzles. The printing head includes n nozzle pairs of the first nozzles and the second nozzles. A control unit causes the printing head to print a TP for determining a use range of the first nozzles and a use range of the second nozzles in the overlapping portion, by m specified nozzle pairs (where 0≤m<n) of the first nozzles and the second nozzles used for ejection of the first liquid of the nozzle pairs. The control unit determines the use ranges, based on density of a specified region from a first printing position of the first nozzle to a second printing position of the second nozzle on the TP.