Image Density Fluctuation Control in Image Forming Apparatus

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Solution Overview

Problem

Existing image forming apparatuses face challenges in maintaining consistent image density due to fluctuations in the electric field between the image carrier and developer carrier, leading to increased processing time and toner consumption when attempting to correct image density fluctuations using special toner patterns.

Innovation Solution

An image forming apparatus that includes rotary members forming toner images and a controller determining image forming conditions based on measured image density fluctuations, allowing for adaptive adjustments without the need for additional toner patterns, thereby reducing image density fluctuations and preventing further degradation from measurement errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If special toner patterns are formed for inspection to determine banding correction, then image density accuracy is improved, but processing time is lengthened and toner consumption increases

Engineering Contradiction:

Improveimage density accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent makes the regular toner pattern serve multiple functions: it is used both for normal image formation and for inspection/banding correction determination. By analyzing the uniformity of the toner pattern formed during regular operation, the system can detect image density fluctuations and determine correction parameters without requiring separate inspection patterns, thereby eliminating additional processing time and toner consumption while maintaining measurement accuracy

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If special toner patterns are formed for inspection to determine banding correction, then image density accuracy is improved, but toner consumption increases

Engineering Contradiction:

Improveimage density accuracyVSAvoidtoner consumption

Core Design Contradiction:

Measurement precisionVSLoss of substance

Solution Approach 1:

The patent makes the regular toner pattern serve multiple functions: it is used both for normal image formation and for inspection/banding correction determination. By analyzing the uniformity of the toner pattern formed during regular operation, the system can detect image density fluctuations and determine correction parameters without requiring separate inspection patterns, thereby eliminating additional toner consumption while maintaining measurement accuracy

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If image forming conditions are periodically changed to cancel fluctuation, then image density fluctuation is reduced, but measurement error may lead to aggravated fluctuation

Engineering Contradiction:

Improveimage density uniformityVSAvoidcorrection reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the system measures image density fluctuations from the toner pattern, determines correction parameters, applies the correction, and then verifies the correction effectiveness. This closed-loop feedback ensures that corrections are based on accurate measurements and can be adjusted or terminated if measurement errors are detected, preventing aggravation of fluctuations while maintaining image density uniformity

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 effectively reduces image density fluctuations and prevents adverse errors without increasing processing time or toner consumption, ensuring consistent image quality by determining image forming conditions based on measured data and terminating adjustments when high measurement errors are detected.

Implementation Method 1

a photoreceptor (40) to form a latent image by exposure

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

a developing device (61) to develop the latent image with toner

Methodology Applied

Scientific EffectElectrostatic Attraction: Electrostatics

Implementation Method 3

a transfer device to transfer the toner image formed on the photoreceptor (40) to a transfer belt (10)

Methodology Applied

Scientific EffectElectrostatic Transfer: Electrostatics

Data Source

PatentUS9128402B2Image forming apparatus capable of effectively preventing image density fluctuation

Publication Date: 2015.09.08 RICOH CO LTD

AI summary

An image forming apparatus includes an image forming unit including rotary members to form a toner image corresponding to image data, in which the image forming unit forms a toner pattern for detecting image density fluctuation; and an image forming condition determination controller to perform image forming processing to ultimately transfer the toner image onto a recording medium. In the image forming apparatus, the controller measures a periodic image density fluctuation occurring in a rotation cycle of the rotary members based on a detection result of a toner pattern; performs image forming condition determination processing to determine an image forming condition to reduce the image density fluctuation based on measured image density fluctuation data; and determines whether or not the image density fluctuation data measured multiple times satisfies a predetermined control termination condition.