Inkjet Printing Apparatus Adaptive Cleaning Ejection
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Solution Overview
Problem
Inkjet printing apparatuses face issues with color mixing due to ink viscosity changes and foreign matter accumulation, leading to ejection failures and deflections, which existing countermeasures like capping and wiping units do not fully address when the print head is idle for extended periods.
Innovation Solution
An inkjet printing apparatus that implements a pre-printing cleaning ejection mechanism using varying ink volumes based on elapsed time since the last wiping operation, with a first volume for immediate ejection failures and a second, increased volume for preventing color mixing after a predetermined time, minimizing waste ink production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single wiper is used to wipe multiple color ink ejection ports, then device size and cost are reduced, but color mixing occurs during the wiping operation
Solution Approach 1:
The patent applies preliminary action by performing a cleaning ejection operation before the actual printing operation. This cleaning ejection removes any ink that may have mixed during the wiping process, preventing color mixing from affecting the printed output. The cleaning ejection is executed as a preliminary step to ensure ink ejection ports are clear of mixed ink before printing begins
2Object-generated harmful factors
If a cleaning ejection is performed after the wiping operation, then color mixing is prevented, but waste ink is generated
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the ink ejection volume based on the elapsed time since the last wiping operation. When the elapsed time exceeds a predetermined threshold, a larger cleaning ejection volume is used to prevent color mixing. When the elapsed time is within the threshold, a smaller ink volume is sufficient. This adaptive parameter adjustment prevents color mixing while minimizing waste ink generation
3Reliability
If the ink ejection ports are left open during idle time, then ink viscosity changes and foreign matter accumulates causing ejection failures, but capping the ports creates color mixing when wiped after idle period
Solution Approach 1:
The patent applies preliminary action by executing a cleaning ejection operation before printing resumes after an idle period. This cleaning ejection removes viscous ink and foreign matter that accumulated during the idle time, preventing ejection failures. The cleaning is performed as a preliminary step before actual printing, ensuring reliable ink ejection without causing color mixing during the cleaning process itself
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
Effectively prevents color mixing and ejection failures by adapting the cleaning ejection volume to the elapsed time since the last wiping operation, ensuring reliable inkjet printing while minimizing waste ink.
Implementation Method 1
a cleaning ejection unit to execute cleaning ejections for expelling inks not suited for the printing operation from the printing unit
Implementation Method 2
when a solvent in ink evaporates from the ink ejection ports increasing a viscosity of ink near the ink ejection ports
Data Source
AI summary
This invention prevents a possible color mixing, that may occur more than a predetermined time after the wiping operation, by executing a pre-printing cleaning ejection while at the same time minimizing the amount of waste ink produced by the cleaning ejection. To this end, if a color mixing is determined as being likely to occur an elapsed time after the previous wiping operation, the pre-printing cleaning ejection uses a second ink volume U, which represents both the color mixing elimination ink volume and the ejection failure elimination ink volume. If it is decided that there is no likelihood of the color mixing occurring the elapsed time after the wiping operation, the pre-printing cleaning ejection uses the first ink volume D which represents only the ejection failure elimination ink volume.