Ink Viscosity Detection for Nozzle Clogging Prevention

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Solution Overview

Problem

Image forming apparatuses face challenges in identifying and addressing nozzles with high viscosity ink, which can lead to ejection failures due to clogging, as existing systems lack effective methods to differentiate between normal and high-viscosity nozzles based on ink viscosity changes over time.

Innovation Solution

The apparatus includes temperature and humidity sensors to calculate ink viscosity for each nozzle, determining high-viscosity nozzles and applying a modified drive waveform to ensure reliable ink ejection, thereby preventing nozzle clogging and maintaining image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the apparatus uses a single threshold for determining high-viscosity nozzles, then the determination process is simple, but it cannot accurately differentiate between nozzles with temporarily elevated viscosity and those with permanently high viscosity

Engineering Contradiction:

Improveviscosity measurement accuracyVSAvoiddetermination process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary viscosity measurements at multiple time points before final determination. By measuring viscosity at different elapsed times and comparing the temporal changes, the system can identify nozzles with permanently high viscosity versus those with temporary fluctuations, enabling more accurate differentiation before committing to a final classification

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from multiple viscosity measurements taken at different time points to iteratively refine the determination of high-viscosity nozzles. By comparing viscosity values across time and adjusting the classification based on the pattern of change, the system improves measurement accuracy while maintaining a manageable determination process

Inventive Principle:

Principle #23Feedback

2Reliability

If the apparatus performs forced ejection for all nozzles to prevent clogging, then all nozzles are maintained, but ink is wasted and productivity decreases

Engineering Contradiction:

Improvenozzle functionalityVSAvoidimage formation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system applies different maintenance strategies to different nozzles based on their individual viscosity characteristics. Only nozzles identified as having permanently high viscosity undergo forced ejection, while nozzles with normal or temporarily elevated viscosity continue normal operation. This localized approach maintains nozzle reliability where needed while preserving overall productivity

Inventive Principle:

Principle #3Local quality

3Loss of time

If the apparatus determines high-viscosity nozzles using only a single viscosity threshold, then the determination is quick, but it misidentifies nozzles with temporary viscosity increases

Engineering Contradiction:

Improvedetermination timeVSAvoidnozzle classification accuracy

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system performs viscosity measurements at multiple time points (excessive action) to ensure accurate classification, but only applies forced ejection to the subset of nozzles that truly require it (partial action). This approach accepts the time cost of multiple measurements as necessary to avoid the greater time loss from misclassification and unnecessary maintenance operations

Inventive Principle:

Principle #16Partial or excessive 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

This approach allows for early prediction and prevention of ejection failures by identifying high-viscosity nozzles and applying enhanced ejection techniques, ensuring consistent ink flow and reducing the likelihood of nozzle clogging, thus maintaining image quality and extending the lifespan of the apparatus.

Implementation Method 1

The piezoelectric elements change volumes of the pressure chambers to eject the ink from the nozzles

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The laser sensor irradiates ink ejected from the nozzles with a laser to detect reflected light

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11292249B2Image forming apparatus

Publication Date: 2022.04.05 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

An image forming apparatus includes a recording head, a controller, a first detector, and a second detector. The controller calculates a viscosity of ink in each of nozzles based on a temperature, a humidity, and an elapsed time. The controller determines, among the nozzles, a nozzle in which the viscosity is equal to or higher than a threshold to be a high-viscosity nozzle. The controller acquires non-ejection information indicating an ejection disabled nozzle that is disabled to eject the ink. The controller acquires a viscosity of the ink in the ejection disabled nozzle. The controller calculates an average value of viscosities of the ink in the plurality of nozzles. The controller compares the viscosity of the ink in the ejection disabled nozzle with the average value of the viscosities of the ink in the nozzles. The controller determines whether or not to change a contribution value based on a comparison result.