Inkjet Head Multi-Pass Recording Ratio Control
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Solution Overview
Problem
Existing liquid droplet ejecting apparatuses, such as ink jet printers, face issues with color unevenness due to changes in the ejection order of inks during bidirectional printing, and similar problems occur with liquid evenness in other droplet ejecting systems.
Innovation Solution
A liquid droplet ejecting apparatus with a recording head that includes multiple nozzle sets for different liquids, and a control system that performs multi-pass recording by adjusting the ratio of dot recording using each liquid in alternating passes to maintain optimal distribution across the recording medium, ensuring that the first half and second half of the passes prioritize different liquids to minimize color or liquid unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bidirectional printing is performed with fixed ejection order, then printing speed is improved, but color unevenness occurs due to change of ejection order
Solution Approach 1:
The patent applies dynamics by making the ejection order dynamic rather than fixed. The control portion changes the ejection order of ink droplets based on the scanning direction (outward path vs. return path), adapting the printing process to the bidirectional movement to maintain consistent color quality regardless of printing speed.
Solution Approach 2:
The patent changes the parameter of ejection order based on the scanning pass. By adjusting which nozzles eject ink and in what sequence during outward versus return passes, the system compensates for the directional changes in bidirectional printing, preventing color unevenness while maintaining high printing speed.
2Productivity
If ejection order of inks is changed for speed optimization, then productivity is improved, but liquid evenness deteriorates
Solution Approach 1:
The system dynamically adjusts the ejection order based on the current scanning direction. During outward path scanning, one ejection sequence is used, while during return path scanning, a different ejection sequence is applied, ensuring consistent liquid distribution regardless of the directional change.
Solution Approach 2:
The control portion uses feedback from the scanning direction information to determine the appropriate ejection order. By monitoring whether the head is moving in the outward or return direction, the system selects the corresponding ink ejection sequence to maintain liquid evenness.
3Reliability
If mask pattern is used to vary yellow ink ejections, then nozzle use deviation is suppressed, but device complexity increases
Solution Approach 1:
The patent varies the ejection parameters (which nozzles eject, ejection timing, and ejection sequence) based on the scanning direction. This parameter adjustment balances the usage of different nozzles without requiring physical mask patterns, achieving reliable nozzle utilization through software control.
Data Source
AI summary
A liquid droplet ejecting apparatus executes multi-pass recording constituted of N scan passes including a scan pass for an outward path and a scan pass for a return path (N being an integer of 2 or more). When a proportion of executions of dot recording using a first liquid in each scan pass is made a first recording ratio, and a proportion of executions of dot recording using a second liquid in each pass is made a second recording ratio, the first recording ratio and the second recording ratio are set such that, in a first half of the N scan passes, a total ratio of the first recording ratio is larger than a total ratio of the second recording ratio, and in a second half of the N scan passes, a total ratio of the second recording ratio is larger than a total ratio of the first recording ratio.