Inkjet Head Drive Method Using Variable Droplet Sizes to Suppress Liquid Gathering
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Solution Overview
Problem
Conventional inkjet recording methods face challenges in suppressing liquid gathering of interpolation dots to interpolate discharge defective nozzles, leading to image quality deterioration, especially when viscosity of the liquid is low or the recording medium has low ink absorbency.
Innovation Solution
The method involves forming interpolation dots using large droplets from adjacent nozzles while ensuring adjacent dots are formed as small droplets to prevent liquid gathering, with specific dot diameter ranges (115% to 250% of medium droplets for interpolation dots and 50% to 85% of medium droplets for small dots) to maintain image quality and prevent white streaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interpolation recording is performed by allocating two nozzles on both sides of a discharge defective nozzle and spreading droplets, then discharge defective nozzles can be interpolated, but recording speed is greatly lowered
Solution Approach 1:
The invention changes the droplet size parameter by discharging a large droplet specifically for interpolation dots (with diameter of 115% to 250% of normal dots) to cover the white streak area, and simultaneously changes the droplet size of adjacent dots to small droplets (50% to 85% of normal dots) to prevent liquid gathering, thereby resolving the contradiction between image quality and recording speed
2Productivity
If dot diameter of interpolation dot is set to be large to interpolate discharge defective nozzle, then recording speed can be maintained, but liquid gathering occurs and white streaks cannot be suppressed
Solution Approach 1:
The invention applies local quality by making different parts of the recording have different droplet sizes: the interpolation dot has a large droplet size (115% to 250% of normal dots) to cover the white streak, while adjacent dots have small droplet sizes (50% to 85% of normal dots) to prevent liquid gathering, thereby simultaneously achieving image quality improvement and recording speed maintenance
Solution Approach 2:
The invention changes the droplet size parameter dynamically based on the dot type: large droplet for interpolation dots to ensure coverage, and small droplet for adjacent dots to prevent liquid gathering, thus resolving the contradiction between maintaining recording speed and suppressing white streaks
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
In order to address the issue of suppressing liquid slippage by interpolation dots that are for interpolating discharge-defective nozzles and the issue of preventing reduction in image quality, the present invention has: an inkjet head capable of selectively discharging large droplets, medium droplets, and small droplets from each of a plurality of nozzles; and a control unit that forms images, using a single-pass method, by discharging medium droplets from each of the plurality of nozzles and, if there is a discharge-defective nozzle, discharges droplets from another nozzle and forms interpolation dots for interpolating the discharge-defective nozzle. The control unit forms, by using large droplets, an interpolation dot DS for interpolating the discharge-defective nozzle and forms, by using small droplets, at least one adjacent dot D2b that comes in contact with the interpolation dot DS.