Ink Ejection Head Pressure Equalization Before Detachment

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Solution Overview

Problem

Ink-jet printers face issues with ink leakage when the ink ejection head is detached due to residual pressures in the ink supply channels and head, especially when ink cartridges of different heights cause uneven ink states before suction, leading to insufficient or excessive ink removal.

Innovation Solution

A liquid ejection apparatus with separate nozzle arrays and supply channels for each liquid, controlled by a system that stops pressurization and performs controlled discharge of ink before detachment, ensuring balanced ink removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single suction cap is used to evenly suck out inks from multiple nozzle arrays, then the suction operation is simplified, but ink leakage occurs in supply channels with higher residual pressure and air backup occurs in supply channels with lower residual pressure

Engineering Contradiction:

Improvesuction operationVSAvoidink leakage prevention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The suction cap is divided into multiple independent suction units, each corresponding to a specific nozzle array and supply channel. Each suction unit can independently control the suction amount and suction timing for its associated supply channel, allowing differentiated pressure equalization based on individual channel characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each suction unit is configured with different suction characteristics tailored to the specific supply channel it serves. The suction amount, suction speed, and suction timing are locally optimized for each channel based on its residual pressure state, ink volume, and height position, rather than applying uniform suction to all channels.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If large-capacity ink cartridges are mounted at different heights to fit the main body, then the cartridges can be accommodated, but the ink states differ between supply channels due to height differences

Engineering Contradiction:

Improveink capacityVSAvoidink state uniformity

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The suction amount and suction timing for each suction unit are determined based on the height position of its corresponding ink cartridge. Lower cartridges (with higher residual pressure) receive different suction treatment compared to higher cartridges, locally optimizing the pressure equalization for each channel's specific conditions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes the suction parameters (suction amount, suction timing, suction speed) according to the height position and residual pressure state of each ink cartridge. This dynamic parameter adjustment compensates for the height differences and ensures uniform ink state across all supply channels.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If ink supply channels are pressurized to supply ink to the ejection head, then ink flow is maintained, but residual pressure causes ink leakage when the head is detached

Engineering Contradiction:

Improveink supply efficiencyVSAvoidink leakage

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Before detaching the ejection head, the system performs preliminary suction operations through the divided suction units to remove residual ink from each supply channel. This preliminary action equalizes the pressure in each channel and prevents ink leakage upon detachment, while maintaining normal pressurization during operation.

Inventive Principle:

Principle #10Preliminary action

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 ink leakage by equalizing pressures and ensuring complete ink discharge, maintaining the ink ejection head's condition for safe detachment.

Implementation Method 1

suck the inks out of the ink supply channels and the ink ejection head with a cleaning unit

Methodology Applied

Scientific EffectSuction: Suction

Implementation Method 2

a first pressurization unit which pumps the first liquid to the liquid ejection head through the first liquid supply channel

Methodology Applied

Scientific EffectPressurization: Pressurisation

Data Source

PatentUS12629940B2Liquid ejection apparatus, and control method and computer readable medium storing a program for controlling the same

Publication Date: 2026.05.19 CANON KK

AI summary

A liquid ejection apparatus including: a liquid ejection head having first and second nozzle arrays that eject first and second liquids, respectively; first and second liquid supply channels which supply the first and second liquids inside first and second liquid containing units to the liquid ejection head, respectively; first and second pressurization units which pump the first and second liquids to the liquid ejection head through the first and second liquid supply channels; and a control unit configured, in a case of preparing for detaching the liquid ejection head, to control the first and second pressurization units to stop pumping, respectively, and to control the liquid ejection head to discharge the first and second liquids from the first and second nozzle arrays, respectively, while controlling amounts of the first and second liquids discharged from the first and second nozzle arrays, respectively, in the liquid discharge operation.