Inkjet Head Correction Control for Defective Nozzle Streak Suppression
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Solution Overview
Problem
Conventional inkjet recording devices experience a decrease in image quality due to the occurrence of white or color streaks when correcting defective nozzles, as ink droplets from downstream recording heads are less affected by droplet settling interference and reach the drying unit sooner, leading to uneven ink distribution.
Innovation Solution
The control unit adjusts the amount of ink discharged to correction pixel regions adjacent to defective nozzles, increasing the amount from upstream heads and reducing it from downstream heads to compensate for droplet settling interference, thereby maintaining consistent ink distribution and reducing streaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of ink discharged to correction pixel regions is increased to suppress white streaks from droplet settling interference, then the occurrence of white streaks is reduced, but color streaks occur in correction pixel regions due to excessive ink accumulation
Solution Approach 1:
The patent applies different ink discharge amounts to different recording heads based on their position. Upstream recording heads discharge increased ink amounts to correction pixel regions to compensate for droplet settling interference, while downstream recording heads discharge reduced ink amounts to prevent color streaks. This localized differentiation resolves the contradiction between suppressing white streaks and preventing color streaks.
Solution Approach 2:
The patent changes the ink discharge amount parameter based on the recording head's position in the movement direction. By adjusting this parameter differently for upstream and downstream heads, the system optimizes ink distribution to eliminate both white and color streaks while maintaining image quality.
2Reliability
If ink droplets are discharged to correction pixel regions adjacent to defective nozzles, then the defective pixel regions can be compensated, but droplet settling interference causes ink droplets to move to adjacent pixel regions creating white streaks
Solution Approach 1:
The patent applies preliminary anti-action by discharging additional ink from upstream recording heads to correction pixel regions before the drying process occurs. This pre-compensation counteracts the harmful droplet settling interference that would otherwise cause white streaks, allowing defective nozzle correction without image quality degradation.
3Device complexity
If downstream recording heads discharge normal ink amounts to correction pixel regions, then the recording process is simple, but ink droplets reach the drying unit too quickly to be affected by droplet settling interference, causing color streaks
Solution Approach 1:
The patent implements local quality by differentiating ink discharge amounts based on recording head position. Downstream recording heads discharge reduced ink amounts to correction pixel regions, preventing color streaks while maintaining simple control logic. This localized adjustment resolves the contradiction between control simplicity and image quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses the occurrence of white and color streaks, ensuring high image quality by optimizing ink distribution across the recording medium, even when defective nozzles are corrected.
Implementation Method 1
The drying unit is arranged on a downstream side relative to the recording head in a direction of movement of the recording medium to dry the recording medium
Data Source
AI summary
In an inkjet recording device, when a defective nozzle in a recording head is corrected, a control unit increases the amount of ink discharged to a correction pixel region adjacent to a defective pixel region corresponding to the defective nozzle in an intersection direction as compared with the amount of ink discharged to each of other pixel regions. The control unit reduces the amount of ink discharged to the correction pixel region by the recording head arranged on a downstream side in the direction of movement of a recording medium as compared with the amount of ink discharged to the correction pixel region by the recording head arranged on an upstream side in the direction of movement of the recording medium.