Inkjet Head Cleaning with Piezo Vibration for Fast Nozzle Unclogging

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Solution Overview

Problem

Existing inkjet printers face challenges in quickly and effectively removing clogging caused by pigment precipitation (caking) in the nozzles of the liquid discharge head, leading to prolonged downtime and difficulty in restoring normal printing operations.

Innovation Solution

A maintenance device with a cap and circuitry that applies drive waveforms to piezoelectric elements to vibrate cleaning liquid, facilitating its circulation and replacement of ink within the nozzles, using a cap to form a space filled with cleaning liquid and applying vibrations to accelerate the diffusion of caking and unclog the nozzles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cap is attached to the nozzle surface to form a space filled with cleaning liquid, then the cleaning liquid can be drawn into the head interior through nozzles, but the time required for the cleaning liquid to diffuse and remove clogging is extended

Engineering Contradiction:

Improveclogging removal effectivenessVSAvoidmaintenance time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies vibration to the cleaning liquid in the space between the cap and nozzle surface. The vibration unit generates vibratory motion that accelerates the diffusion of cleaning liquid into the nozzle interior, significantly reducing the time required for the cleaning liquid to reach and dissolve pigment precipitation (caking) compared to static cleaning methods.

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The patent uses periodic drive waveforms to control the piezoelectric elements, creating oscillating pressure fields that enhance the circulation and penetration of cleaning liquid through the nozzles. This periodic action maintains continuous motion of the cleaning liquid, preventing stagnation and improving diffusion efficiency over time.

Inventive Principle:

Principle #19Periodic action

2Productivity

If vibration is applied to accelerate cleaning liquid diffusion, then unclogging speed is improved, but the device complexity increases due to additional vibration components

Engineering Contradiction:

Improveunclogging speedVSAvoidmaintenance device structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent integrates the vibration function into the existing piezoelectric elements that are already part of the inkjet head structure. These piezoelectric elements serve dual purposes: normal ink ejection during printing and vibration generation during maintenance mode. This eliminates the need for separate vibration actuators, reducing overall device complexity while maintaining high unclogging speed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The maintenance system utilizes the head's own piezoelectric elements and internal structure to generate the necessary vibration for cleaning. The system is self-contained, using existing components rather than requiring external vibration sources or additional mechanical assemblies, thereby minimizing added complexity.

Inventive Principle:

Principle #25Self-service

3Reliability

If multiple drive waveforms are applied to circulate cleaning liquid through multiple nozzles, then cleaning coverage is improved, but the control complexity increases

Engineering Contradiction:

Improvecleaning coverageVSAvoidcontrol system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the nozzle array into multiple groups, with each group controlled by a separate drive waveform. This segmentation allows independent control of different nozzle regions, enabling comprehensive cleaning coverage across all nozzles while simplifying the control logic for each individual group compared to controlling all nozzles simultaneously with a single complex waveform.

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

The solution enables rapid unclogging of nozzles, reducing downtime by enhancing the diffusion and circulation of cleaning liquid, thereby restoring normal printing operations efficiently.

Implementation Method 1

applies a drive waveform to a piezoelectric element of the head to apply vibration to the cleaning liquid in the space

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

applies a drive waveform to a piezoelectric element of the head

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

enhancing the diffusion and circulation of cleaning liquid, thereby restoring normal printing operations

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12545029B2Head maintenance device, image forming apparatus, and head maintenance method

Publication Date: 2026.02.10 RICOH CO LTD

AI summary

Ahead maintenance device includes a cap and circuitry. The cap is detachably attachable to a nozzle surface of a head to cover the nozzle surface having a nozzle. The circuitry causes the cap to contact the nozzle surface of the head to form a space between the nozzle surface and the cap filled with a cleaning liquid, and applies a drive waveform to a piezoelectric element of the head to apply vibration to the cleaning liquid in the space. The drive waveform causes the head to draw the cleaning liquid into an interior of the head through the nozzle.