Inkjet Printer Flow Path Bubble Removal

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Solution Overview

Problem

Inkjet printing apparatuses with ink circulation systems face issues with air bubbles remaining in branch flow paths, leading to potential ink ejection failures due to insufficient ink filling.

Innovation Solution

The implementation of a control method that utilizes the head replacement flow path and valve to fill the relief flow path with ink, removing air bubbles by intermittently opening and closing the head replacement valve to direct air bubbles into the sub-tank, ensuring the branch flow paths are fully inked.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a branch flow path is provided to connect the sides of a supply flow path upstream and downstream of the supply pump, then ink circulation is improved, but air bubbles remain in the branch flow path causing ink ejection failure

Engineering Contradiction:
Improveink circulationVSAvoidair bubbles in branch flow path
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by filling the branch flow path with ink before normal printing operations begin. The control unit executes a specific filling operation that opens the head replacement valve and activates the supply pump to force ink through the branch flow path, ensuring air bubbles are expelled beforehand. This preliminary ink filling prevents air bubbles from entering the print head during subsequent printing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of air bubbles in the branch flow path into a benefit by using the head replacement valve and supply pump to actively manage and expel these air bubbles. The system utilizes the existing branch flow path structure and converts it from a potential source of problems into a controlled pathway where air bubbles can be deliberately removed through the valve during the filling operation, transforming a harmful element into a manageable aspect of the system.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If the supply pump drives ink through the supply flow path, then ink is supplied to the print head, but the branch flow path cannot be sufficiently filled with ink

Engineering Contradiction:
Improveink supply to print headVSAvoidink filling in branch flow path
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies dynamics by making the head replacement valve controllable and switchable between open and closed states. During normal printing operations, the valve remains closed to maintain standard ink flow. During the filling operation, the valve is dynamically opened to allow ink to enter the branch flow path, and then closed again once filling is complete. This dynamic control of the valve state enables the system to adapt its flow characteristics to achieve both efficient ink supply and complete branch path filling.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses the head replacement valve as an intermediary element to control ink flow into the branch flow path. By positioning and controlling this valve, the system can selectively direct ink into the branch flow path during the filling operation without disrupting the main ink supply to the print head. The valve acts as a mediator that enables controlled ink distribution to different parts of the system at different times.

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 solution effectively prevents air bubbles from entering the print head, reducing the risk of ink ejection failures and ensuring stable printing operations by ensuring all flow paths are fully filled with ink.

Implementation Method 1

a supply pump that drives ink from the ink tank toward the print head through the flow path

Methodology Applied
Scientific EffectPump: Pump

Data Source

PatentEP3424725B1Inkjet printing apparatus and control method of the inkjet printing apparatus
Publication Date: 2020.08.26 CANON KK
  • EP3424725B1 patent drawingFigure 1
  • EP3424725B1 patent drawingFigure 2
  • EP3424725B1 patent drawingFigure 3

AI summary

According to an aspect, an inkjet printing apparatus includes a supply pump (P1) provided in a supply flow path (C2) for supplying ink from a tank (151) to a print head (8), a first flow path (C3) connecting the first position upstream of the supply pump in the supply flow path and the second position downstream of the supply pump in the supply flow path, a second flow path (C5) connecting the tank and the third position downstream of the supply pump in the supply flow path, and an open/close valve (V5) provided in the second flow path and capable of opening and closing the second flow path.