Liquid Ejection Device Nozzle Apportionment Control
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Solution Overview
Problem
Existing liquid ejection devices suffer from concentration irregularities in the images formed on the medium due to deviations in the positions of the heads, making the images appear irregular when viewed with the naked eye.
Innovation Solution
A liquid ejection device with a head unit, movement mechanism, leading nozzle row, and trailing nozzle row, where the controller adjusts the apportionment ratios of the nozzles to decrease sequentially from the first nozzle to the mth nozzle, with a greater change rate at the ends than in the middle, ensuring that concentration irregularity is minimized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the apportionment ratio is kept constant across all nozzles, then the control is simple, but concentration irregularities occur in the image when head positions deviate
Solution Approach 1:
The patent applies local quality by setting different apportionment ratios for different nozzle groups based on their position. The nozzles are divided into multiple groups along the movement direction, with each group having a specifically designed apportionment ratio. This local differentiation compensates for position deviations and ensures uniform image concentration across the entire printing area.
Solution Approach 2:
The patent changes the parameter of apportionment ratio dynamically across different nozzle groups. By adjusting this parameter according to position, the system compensates for head position deviations. The apportionment ratio varies systematically from one end of the head to the other, creating a gradient that corrects for cumulative positioning errors.
2Manufacturing precision
If the apportionment ratio changes uniformly across all nozzles, then the concentration irregularity is reduced, but the change rate should be greater at the ends than in the middle for optimal correction
Solution Approach 1:
The patent implements local quality by assigning different apportionment ratios to different nozzle groups based on their positional characteristics. The end nozzle groups receive larger apportionment ratios while middle groups receive smaller ratios, creating a non-uniform distribution that optimally compensates for position deviations at different locations along the head.
Solution Approach 2:
The patent applies asymmetry by creating an asymmetric apportionment ratio distribution across the nozzles. Rather than using a symmetric or uniform distribution, the system deliberately creates an asymmetric pattern where the apportionment ratios at the ends differ from those in the middle, matching the asymmetric nature of positioning errors that accumulate more at the extremes.
Data Source
AI summary
In a printing device for discharging ink from a plurality of print heads and printing on a print medium, the print heads are arrayed in a direction orthogonal to a movement direction relative to the print medium so that overlapping areas are created which overlap in the movement direction. A change rate of the apportionment ratio between a first nozzle row of an upstream print head in the relative movement direction of the print medium and of a second nozzle row and a downstream print head in the ends in the overlapping areas is greater than the change rate of the apportionment ratio in the middle in the overlapping areas. Concentration irregularity occurring in the overlapping areas of the printed article can thereby be made inconspicuous.