Inkjet Printer Intermittent Flushing for Color Mixture

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Solution Overview

Problem

Inkjet printers face challenges in preventing color mixture between different ink colors, particularly when inks of varying lightness are used, leading to conspicuous issues during printing.

Innovation Solution

The implementation of an intermittent flushing operation in inkjet printers, which involves alternating between discharging ink and standby periods, helps to convect and eliminate mixed ink from sub-heads, reducing color mixture by pulsating the ink and promoting diffusion within the nozzle system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If successive flushing operation is used to clean the ink head, then the nozzles can be cleaned, but color mixture between different ink colors occurs in the first sub-head

Engineering Contradiction:

Improvenozzle cleaning effectivenessVSAvoidcolor mixture

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The ink head is divided into multiple sub-heads (first sub-head and second sub-head) that are integral to each other but function independently. Each sub-head has its own nozzles for different ink colors, allowing separate cleaning and operation to prevent color mixture while maintaining overall structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cleaning process uses periodic flushing operations where ink is discharged in alternating patterns. The intermittent flushing operation includes repeated cycles of discharging ink followed by standby periods, creating periodic action that prevents color mixture by allowing complete drainage and air passage between color changes.

Inventive Principle:

Principle #19Periodic action

2Productivity

If traditional successive flushing operation is used, then ink can be discharged from nozzles, but a large amount of ink is consumed

Engineering Contradiction:

Improveflushing operation effectivenessVSAvoidink consumption

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The intermittent flushing operation replaces continuous successive flushing with periodic cycles of discharge followed by standby periods. This periodic action allows the ink to be flushed in controlled bursts, reducing overall ink consumption while maintaining effective cleaning through the alternating discharge and pause pattern.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system maintains continuous operational readiness by alternating flushing cycles with standby periods. During standby periods, the system prepares for the next flushing cycle, ensuring that the useful action of ink discharge is continuously available when needed while minimizing waste during transition phases.

Inventive Principle:

Principle #20Continuity of useful action

3Object-generated harmful factors

If intermittent flushing operation is implemented, then color mixture is reduced, but the device complexity increases

Engineering Contradiction:

Improvecolor mixture reductionVSAvoidflushing control complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The intermittent flushing operation is implemented as a universal cleaning method that can be applied to all sub-heads in the ink head system. The same control mechanism and operational pattern work for different ink colors and sub-head configurations, providing multi-functionality that reduces overall system complexity despite the sophisticated flushing pattern.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach effectively reduces color mixture during printing, using a smaller amount of ink compared to traditional successive flushing methods, ensuring better print quality and ink efficiency.

Implementation Method 1

The intermittent flushing operation may provide pulsations to the ink in the first sub-head so as to produce convection of the ink

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

The intermittent flushing operation is able to eliminate or reduce color mixture more effectively than successive flushing operations known in the related art

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS11141977B2Inkjet printer and nonvolatile memory storing computer program

Publication Date: 2021.10.12 ROLAND DG CORP

AI summary

An inkjet printer includes a first ink head, an ink collector, and an intermittent flushing controller. The first ink head includes a first sub-head that includes a first nozzle to discharge first ink, a second sub-head that includes a second nozzle to discharge second ink different from the first ink, and a nozzle surface provided with the first nozzle and the second nozzle. The ink collector collects the ink discharged from the first ink head. The intermittent flushing controller performs an intermittent flushing operation for at least the first sub-head. The intermittent flushing operation involves repeating a first operation and a second operation for a predetermined number of iterations. The first operation involves discharging the first ink into the ink collector from the first nozzle a predetermined number of times. The second operation involves being on standby for a predetermined time without discharging the first ink from the first nozzle.