Photoconductor Surface Potential Detection via Developing Current

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Solution Overview

Problem

Existing image forming apparatuses based on electrophotography rely on expensive surface potential sensors to detect the surface potential of photoconductor drums, which can be inaccurate due to toner splashes, necessitating a cost-effective and accurate method for surface potential acquisition.

Innovation Solution

An image forming apparatus that includes an image carrier, a charging device, a developing device, a developing power source, a current measuring device, and a calculation device, where an electrostatic latent image is formed on the image carrier, and the surface potential is calculated based on the developing current measured by the current measuring device, allowing for surface potential estimation without relying on expensive sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a surface potential sensor is used to detect the surface potential of the photoconductor drum, then the surface potential can be measured, but the cost increases and measurement accuracy decreases due to toner splash contamination

Engineering Contradiction:

Improvesurface potential measurement accuracyVSAvoidtoner splash contamination

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful function of the surface potential sensor by removing it from the system. Instead of using a physical sensor that can be contaminated by toner, the invention uses a current measurement method that indirectly obtains surface potential information without direct contact with the photoconductor surface, thereby eliminating the contamination problem while maintaining measurement capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary measurement approach by using current flow as a mediator to infer surface potential. Rather than measuring surface potential directly with a sensor, the system measures the current flowing through the photoconductor drum during development, which serves as an indirect indicator of surface potential, avoiding direct exposure to toner contamination

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a surface potential sensor is used to detect the surface potential of the photoconductor drum, then the surface potential can be measured, but the cost increases

Engineering Contradiction:

Improvesurface potential measurement capabilityVSAvoidapparatus cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive surface potential sensor with a cost-effective current measurement approach using standard amperometric sensors. This substitution uses cheaper, more readily available components that can be easily manufactured and integrated into the image forming apparatus, significantly reducing overall system cost while maintaining measurement functionality

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the mechanical/electrical surface potential sensor system with an electrical current measurement system. By replacing the direct potential sensing mechanism with an indirect current-based measurement method, the invention eliminates complex sensor hardware and reduces manufacturing costs while achieving the same functional objective

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables accurate and cost-effective acquisition of the surface potential of the photoconductor drum, improving image quality by applying an appropriate developing bias voltage, thus reducing the reliance on expensive surface potential sensors and minimizing errors caused by toner splashes.

Implementation Method 1

a charging device (63) electrically charges the image carrier (65)

Methodology Applied

Scientific EffectElectrical charging: Electrostatics

Implementation Method 2

a developing device (64) forms a toner image, by supplying toner to the image carrier (65) and developing the electrostatic latent image

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatic Induction

Implementation Method 3

a current measuring device (646) measures a developing current flowing in the developing device (64)

Methodology Applied

Scientific EffectElectrical current measurement: Conduction (electrical)

Data Source

PatentUS11592760B2Image forming apparatus that detects surface potential of image carrier with high accuracy

Publication Date: 2023.02.28 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

An image forming apparatus includes a developing device that forms a toner image, by developing an electrostatic latent image formed on a photoconductor drum, a charging device that electrically charges the photoconductor drum, a developing power source that applies a predetermined developing bias voltage to the developing device, and a calculation device that calculates a surface potential of the photoconductor drum, on a basis of the developing current flowing in the developing device. The developing power source applies the developing bias voltage in a plurality of levels, to the developing device. A current measurement device measures a developing current, with respect to the developing bias voltage of each level. The calculation device calculates the surface potential, on the basis of each developing current.