Intermediate Ink Tank Pressure Control for Stable Printhead Supply

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Solution Overview

Problem

Existing printing apparatuses experience variations in ink supply pressure due to the restoring force of liquid chamber components, leading to unstable ink discharge performance.

Innovation Solution

The use of an intermediate tank with a pressure adjusting unit and check valves to control ink supply pressure, incorporating a restricting unit to limit the displacement of a flexible wall member, ensuring consistent pressure delivery to the discharge head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If the capacity of the liquid chamber increases more than assumed at the time of ink introduction, then the liquid chamber can accommodate more ink, but the restoring force of the constituent members acts when supplying ink, causing higher than assumed ink supply pressure

Engineering Contradiction:

Improveliquid chamber capacityVSAvoidink supply pressure

Core Design Contradiction:

Volume of stationary objectVSStress or pressure

Solution Approach 1:

A pressure adjusting unit is introduced as an intermediary component between the liquid chamber and the discharge head. This unit actively regulates the ink supply pressure by adjusting the capacity of the liquid chamber in response to pressure variations, thereby mediating the interaction between the chamber's restoring force and the discharge requirements, ensuring stable ink supply pressure despite capacity changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The pressure adjusting unit implements a feedback mechanism by detecting variations in ink supply pressure and dynamically adjusting the liquid chamber capacity accordingly. When pressure deviates from the target value, the system modifies the chamber capacity to counteract the deviation, creating a closed-loop control system that maintains stable ink supply pressure.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the liquid chamber capacity varies during operation, then the chamber can adapt to different ink levels, but this causes variations in ink supply pressure affecting discharge stability

Engineering Contradiction:

Improveliquid chamber adaptabilityVSAvoidink discharge stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The pressure adjusting unit continuously monitors ink supply pressure and adjusts the liquid chamber capacity in real-time based on feedback signals. This closed-loop control ensures that despite the chamber's adaptability to different ink levels, the ink supply pressure remains stable, thereby maintaining reliable and consistent ink discharge performance.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The pressure adjusting unit serves as a mediator that decouples the relationship between liquid chamber capacity variations and ink supply pressure. By actively regulating pressure in response to chamber capacity changes, it allows the chamber to be adaptable to different ink levels while preventing these variations from affecting discharge stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 stabilizes ink supply pressure, reducing variations and ensuring consistent ink discharge performance by preventing excessive pressure fluctuations.

Implementation Method 1

a pressure adjusting unit that adjusts a capacity of the liquid chamber to adjust a supply pressure of the ink

Methodology Applied

Scientific EffectPressure adjustment through capacity change:

Implementation Method 2

a first check valve that allows the ink to flow from the container to the liquid chamber, a second check valve that allows the ink to flow from the liquid chamber to the discharge head

Methodology Applied

Scientific EffectCheck valve flow control: Valve

Implementation Method 3

incorporating a restricting unit to limit the displacement of a flexible wall member, ensuring consistent pressure delivery

Methodology Applied

Scientific EffectDisplacement restriction:

Data Source

PatentEP4678402A1Printing apparatus, control method, storage medium, and computer program

Publication Date: 2026.01.14 CANON KK

Figure 1A~1B
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AI summary

An apparatus (1) includes liquid and pressure chambers, a wall member (22) partitioning between the chambers, restricting means restricting the displacement of the wall member, and pressure adjusting means (60) adjusting the pressure in the pressure chamber. The wall member is displaced to increase the capacity of the liquid chamber when the pressure chamber is set in a negative pressure state. The restricting means restricts a displacement range of the wall member when the pressure chamber is set in the negative pressure state. The adjusting means performs a replenishing operation of adjusting the pressure chamber in the negative pressure state so as to introduce the liquid from a container to the liquid chamber, and a supplying operation of adjusting the pressure chamber in a positive pressure state so as to supply the liquid from the liquid chamber to a discharging means.