Ink-jet Recording Head Nozzle Flushing Control
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Solution Overview
Problem
Ink-jet recording apparatuses face issues with nozzle clogging due to increased ink viscosity over time, leading to degraded image quality, especially when printing on sheets of varying sizes, as the ink ejected less frequently accumulates and causes congestion in the nozzles.
Innovation Solution
The apparatus incorporates a conveying belt with flushing areas and a control system that manages ink ejection by classifying nozzles into first and second nozzles, where first nozzles eject less ink during flushing periods when nozzles do not face the sheet, and second nozzles eject more ink when they do, ensuring efficient ink distribution and minimizing nozzle clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flushing processing is performed by ejecting ink from all nozzles at regular intervals, then nozzle clogging is prevented, but ink consumption increases and waste is generated
Solution Approach 1:
The patent applies local quality by differentiating ink ejection amounts among nozzles based on their specific conditions. Nozzles are classified into first nozzles (facing recording medium, requiring normal printing function) and second nozzles (not facing recording medium, available for flushing). Second nozzles eject larger amounts of ink for flushing, while first nozzles maintain normal ejection amounts, optimizing both cleaning effectiveness and ink conservation.
Solution Approach 2:
The patent segments the nozzle group into distinct categories (first nozzles and second nozzles) with different functions. This segmentation allows independent control of ink ejection amounts for each category, enabling targeted flushing of idle nozzles without affecting the printing quality from active nozzles.
2Reliability
If ink is ejected frequently from all nozzles to prevent clogging, then nozzle reliability is maintained, but productivity decreases due to increased processing time
Solution Approach 1:
The patent implements periodic flushing action during intervals between successive printing operations. Flushing processing is performed during the control period when the recording medium is being conveyed, utilizing idle time when nozzles are not actively printing. This periodic flushing maintains nozzle reliability without interrupting the printing workflow, thereby preserving productivity.
Solution Approach 2:
The patent ensures continuous useful action by performing flushing operations during the conveyance period of recording media. The control portion manages the timing so that flushing occurs during intervals between printing operations on successive media, making continuous use of available time without stopping the printing process.
3Reliability
If flushing areas are added to the conveying belt, then nozzle cleaning effectiveness is improved, but device complexity increases
Solution Approach 1:
The conveying belt is designed with multi-functionality by incorporating flushing areas that serve dual purposes: supporting recording media during printing and receiving flushed ink during cleaning operations. This universal design eliminates the need for separate flushing mechanisms, maintaining structural simplicity while improving cleaning effectiveness.
Solution Approach 2:
The flushing areas on the conveying belt act as an intermediary structure that facilitates ink collection during flushing operations. These areas provide a designated zone for ink ejection during cleaning, mediating between the nozzles and the waste collection system without requiring additional complex components.
Data Source
AI summary
A control portion sets, as a control period, a period after arrival, at a position opposite a recording head, of a first recording medium until passage, at the position opposite the recording head, of a last recording medium. The control portion sets nozzles that do not face the recording medium during the control period as first nozzles, and nozzles that face the recording medium during the control period as second nozzles, to make the total amount of ink ejected by each of the first nozzles in flashing processing during the control period smaller than the total amount of ink ejected by each of the second nozzles.