Inkjet Head Capping Humidification to Prevent Nozzle Clogging
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Solution Overview
Problem
Inkjet recording apparatuses using water-based ink face issues with ink viscosity increase and clogging due to moisture evaporation from nozzles during non-printing operations, leading to ejection failures, and existing humidification methods can cause flow pass blockages.
Innovation Solution
A maintenance device with a cap, supply part, air pump, and restriction part to generate a pressure loss of 4σ/R or more, using a humidifying medium to supply humidified air to the nozzle surface, and a restriction part to prevent flow pass blockage by dew condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If air is sent into water through a tube (flow pass) to generate humidified air, then humidified air can be supplied to the cap, but water vapor condensation in the flow pass blocks the passage, making it difficult for air to pass through
Solution Approach 1:
The patent introduces a restriction part as an intermediary component in the flow pass that actively manages water droplet accumulation. This restriction part creates a pressure differential that prevents condensed water droplets from blocking the air flow passage, thereby maintaining reliable humidified air supply without requiring complex heating or drainage systems
Solution Approach 2:
The patent changes the pressure parameter within the flow pass by introducing a restriction part that generates a pressure difference. This parameter change prevents water vapor condensation from blocking the passage by maintaining sufficient air flow velocity and pressure to clear condensed droplets, ensuring continuous humidified air supply
2Stability of the object's composition
If humidified air is supplied to the cap to prevent moisture evaporation from ink, then ink viscosity increase is suppressed, but water droplet blockage in the flow pass disrupts humidified air generation
Solution Approach 1:
The restriction part serves as an intermediary that resolves the conflict between maintaining ink viscosity stability through humidified air supply and preventing flow pass blockage. It creates a pressure differential that ensures continuous air flow through the water, preventing droplet accumulation that would disrupt humidified air generation and thereby maintaining ink viscosity stability
3Device complexity
If a simple tube structure is used to generate humidified air, then device complexity is reduced, but water droplet blockage occurs making air passage difficult
Solution Approach 1:
The patent adds a restriction part as a simple intermediary component to the tube structure. This minimal addition creates the necessary pressure differential to prevent water droplet blockage while maintaining the overall simplicity of the humidified air generation structure, avoiding complex heating elements, pumps, or drainage systems
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
Prevents nozzle clogging by maintaining ink viscosity and ensuring consistent humidified air supply, even in the presence of dew condensation, thereby enhancing the reliability of inkjet recording operations.
Implementation Method 1
generates a loss of pressure of 4σ/R or more (σ: a surface tension of the humidifying medium WM, R: an inner diameter of the supply flow pass)
Implementation Method 2
generates a humidified air by passing air through the humidifying medium
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A maintenance device (30) maintains a head unit (11) including an inkjet head (11). The maintenance device (30) includes a cap (72), a supply part (92), an air pump (95), and a restriction part (96). The cap (72) is attached to a nozzle surface of the inkjet head (12). The supply part (92) stores a humidifying medium, generates a humidified air by passing air through the humidifying medium, and supplies the humidified air to the cap (72). The air pump (95) sends air recovered from the cap (72) to the supply part (92) through a supply flow pass (95N). The restriction part (96) is provided in the supply flow pass (95N), and generates a loss of pressure of 4σ/R or more (σ : a surface tension of the humidifying medium WM, R : an inner diameter of the supply flow pass (95N))).