Photoconductor Point Defect Detection via Charging Current

Solution Overview

Problem

In liquid electrophotography printing, point defects on the photoconductive surface can lead to print quality defects, such as unwanted image artifacts, due to scratches, contaminants, or debris, which are difficult to detect and may result in unnecessary replacement of components, increasing costs and waste.

Innovation Solution

A method to detect point defects by measuring the current resulting from a voltage applied to the photoconductor using a charging component, with processing circuitry analyzing the data to identify spikes or peaks indicative of defects, allowing for timely remedial action and reducing unnecessary component replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If point defects on the photoconductive surface are not detected, then the print apparatus continues operating, but print quality defects occur and components are unnecessarily replaced

Engineering Contradiction:

Improveprint qualityVSAvoidcomponent replacement

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The system performs preliminary detection of point defects on the photoconductive surface by measuring charging current variations before printing operations proceed. This advance detection allows for timely cleaning or replacement of defective components, preventing print quality defects and avoiding unnecessary component replacements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual inspection methods with an automated electrical measurement system. By measuring charging current variations through a charging roller or corona wire, the system automatically detects point defects without requiring physical contact or visual inspection, enabling precise and efficient defect identification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If manual inspection methods are used to detect point defects, then the detection process is simple, but the detection precision is insufficient and defects are difficult to detect

Engineering Contradiction:

Improvedefect detection accuracyVSAvoiddetection system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual inspection methods with an automated electrical measurement system. By measuring charging current variations through a charging roller or corona wire, the system automatically detects point defects without requiring physical contact or visual inspection, enabling precise and efficient defect identification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The charging roller or corona wire serves as an intermediary between the detection system and the photoconductive surface. This intermediary component enables indirect detection of point defects through electrical measurements, avoiding the need for direct contact or complex visual inspection systems while maintaining high detection precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the photoconductive surface is frequently replaced as a preventive measure, then print quality is maintained, but operational costs increase and resource utilization decreases

Engineering Contradiction:

Improveprint quality consistencyVSAvoidresource utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary detection of point defects on the photoconductive surface by measuring charging current variations before printing operations proceed. This advance detection allows for timely cleaning or replacement of defective components, preventing print quality defects and avoiding unnecessary component replacements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors charging current variations and provides feedback about the condition of the photoconductive surface. This feedback mechanism enables real-time identification of point defects and allows for condition-based maintenance, replacing components only when actually needed rather than following a fixed schedule.

Inventive Principle:

Principle #23Feedback

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

Accurate detection of point defects enables timely cleaning or replacement, reducing print quality defects and operational costs by ensuring the photoconductive surface is maintained effectively, thereby improving print quality and resource utilization.

Implementation Method 1

measuring a current resulting from a voltage that is applied to the photoconductor by a charging component

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12130575B2Determining the existence of point defects in print apparatuses

Publication Date: 2024.10.29 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

A print apparatus is disclosed. The print apparatus includes a photoconductive surface to receive a latent image representative of an image to be printed onto a printable substrate; a charging component to apply a voltage is to be applied to the photoconductive surface as the charging component moves relative to the photoconductive surface; and processing circuitry to receive data indicative of a measurement of a first current resulting from the voltage applied by the charging component; determine, responsive to detecting an increase in the measured first current relative to a reference current, the increase being greater than a first defined threshold current, that there exists a point defect under affecting the latent image; and generate instruction data responsive to determining that there exists a point defect under affecting the latent image. A method and a machine-readable medium are also disclosed.