Liquid Discharge Apparatus Atmosphere Switching for Ink Overflow Prevention

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Solution Overview

Problem

Existing liquid discharge apparatuses face issues with ink overflowing from the storage cap, especially when the head is removed or the storage is inclined, leading to difficulties in preventing ink from flowing out and clogging of paths.

Innovation Solution

The apparatus includes a suction cap, a tank, a first path for suction, a second path connected to the suction cap, and an atmosphere switch that controls the connection between the second path and either a first atmosphere path or a second atmosphere path with a smaller diameter, preventing ink overflow by managing air flow and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate suction path and liquid flow path are provided, then the suction function is improved, but the liquid may still overflow from the storage to the outside

Engineering Contradiction:
Improvesuction functionVSAvoidliquid overflow
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A third path is introduced as an intermediary air supply path between the suction path and the liquid flow path. This third path supplies air to the suction cap during suction operations, preventing negative pressure that would cause liquid to be drawn out through the suction path. The mediator path resolves the contradiction by decoupling the suction function from direct liquid contact while maintaining effective ink removal.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the head is removed from the storage, then the head cleaning is facilitated, but the liquid is likely to overflow from the storage to the outside

Engineering Contradiction:
Improvehead cleaningVSAvoidliquid overflow
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary air supply through the third path before and during head removal. By pre-establishing positive pressure in the storage chamber through dedicated air supply, the system prevents liquid overflow that would occur during head removal. This preliminary action ensures that the storage environment is prepared to maintain liquid containment regardless of head position or removal status.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If air is supplied to the suction cap during suction, then the suction efficiency is improved, but liquid may be drawn out through the suction path

Engineering Contradiction:
Improvesuction efficiencyVSAvoidliquid drawn out
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The air supply function is segmented into two independent paths: the third path supplies air during suction operations to maintain positive pressure and prevent liquid drawout, while the first path is dedicated to liquid flow. This segmentation allows air supply to enhance suction efficiency without causing liquid to be drawn out through the suction path, as each path has its dedicated function and pressure control.

Inventive Principle:
Principle #1Segmentation

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

This configuration effectively prevents ink from overflowing from the storage by managing air flow and pressure, ensuring that ink is sucked into the tank without overflowing, even when the head is removed or the storage is inclined.

Implementation Method 1

The suction device is disposed in the first path between the suction cap and the tank to suck the liquid from the head to the suction cap

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 2

The first atmosphere path having a first diameter connects the second path to atmosphere. The second atmosphere path having a second diameter smaller than the first diameter connects the second path to the atmosphere

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4309900B1Liquid discharge apparatus
Publication Date: 2025.02.19 RICOH CO LTD
  • EP4309900B1 patent drawingFigure 1
  • EP4309900B1 patent drawingFigure 2
  • EP4309900B1 patent drawingFigure 3

AI summary

In a liquid discharge apparatus (1), a head (210) discharges a liquid. A suction cap (200) detachably contacts the head (210) and stores the liquid suctioned from the head (210). A tank (206) stores the liquid fed from the suction cap (200). A first path (201) connects the suction cap (200) and the tank (206). A suction device (205) sucks the liquid from the head (210). A second path (202, 203) is connected to the suction cap (200). A first atmosphere path (208) having a first diameter connects the second path (202, 203) to atmosphere. A second atmosphere path (204) having a second diameter smaller than the first diameter connects the second path (202, 203) to the atmosphere. An atmosphere switch (207) switches to connect the second path (202, 203) with the first atmosphere path (208) or connect the second path (202, 203) with the second atmosphere path (204).