Image Forming Apparatus Potential Controller

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Solution Overview

Problem

Electrophotographic image forming apparatuses face fluctuations in image density due to changes in ambient conditions and over time, which existing process control methods struggle to stabilize effectively.

Innovation Solution

An image forming apparatus with a potential controller that calculates the exposed area potential based on detected surface potential and sets a potential threshold between the unexposed and exposed area potentials, adjusting for changes in the latent image bearer and ambient conditions to maintain stable image density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If process control is executed using fixed potential threshold to stabilize image density, then image density stability is improved, but the control accuracy deteriorates when latent image bearer properties or ambient conditions change

Engineering Contradiction:

Improveimage density stabilityVSAvoidexposed area potential extraction accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The potential threshold is changed from a fixed value to a dynamically adjustable value that adapts to changes in latent image bearer properties and ambient conditions. The controller updates the potential threshold based on detected surface potential variations, ensuring accurate exposed area potential extraction under varying operating conditions while maintaining image density stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The potential threshold parameter is modified based on detected changes in surface potential. When the latent image bearer properties or ambient conditions change, the controller adjusts the potential threshold parameter to maintain accurate differentiation between exposed and unexposed areas, thereby preserving measurement precision across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If potential threshold is fixed between initial unexposed and exposed area potentials, then exposed area potential can be extracted initially, but extraction reliability deteriorates when latent image bearer changes or ambient conditions vary

Engineering Contradiction:

Improveexposed area potential extractionVSAvoidextraction reliability under varying conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system implements feedback by continuously monitoring surface potential and using this information to adjust the potential threshold. The controller detects changes in surface potential caused by latent image bearer degradation or ambient condition variations, and automatically updates the potential threshold to maintain reliable exposed area potential extraction throughout the apparatus lifecycle.

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

The solution ensures reliable image density stabilization by dynamically adjusting image forming conditions, effectively addressing fluctuations caused by changes in the latent image bearer and ambient conditions.

Implementation Method 1

a charger (9) to charge a surface of the latent image bearer (3)

Methodology Applied

Scientific EffectElectrostatic charging: Electrostatic Induction

Implementation Method 2

an exposure device (1) to expose the surface of the charged latent image bearer (3) with light according to image data, thereby forming an electrostatic latent image thereon

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Implementation Method 3

a potential detector (5) to detect a surface potential at a detection position disposed, on the surface of the latent image bearer (3), between an exposure position and a development position

Methodology Applied

Scientific EffectElectrostatic field detection: Electric Field

Implementation Method 4

a developing device (4) to supply toner to the electrostatic latent image on the latent image bearer (3) to develop the electrostatic latent image

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatic Induction

Data Source

PatentUS9513585B2Image forming apparatus which sets image forming condition based on calculated exposed area potential

Publication Date: 2016.12.06 RICOH CO LTD

AI summary

An image forming apparatus includes a latent image bearer; a charger; an exposure device; a developing device; a potential detector to detect a surface potential at a detection position between an exposure position and a development position on the latent image bearer in a direction of rotation of the latent image bearer; and a potential controller to determine an image forming condition. The potential controller includes a potential calculator to calculate an exposed area potential based on a detected potential smaller in charging polarity than a potential threshold, out of the detected surface potential, and a threshold determiner to set the potential threshold between the exposed area potential and an unexposed area potential of the latent image bearer based on at least one of a change in the unexposed area potential, a change with time of the latent image bearer, and a change in an ambient condition.