Image Forming Apparatus Cleaner Control for Charging Roller Uniformity

Solution Overview

Problem

Image forming apparatuses face challenges in maintaining high image quality due to uneven contamination levels on charging rollers, which affect the charging current differences and cleaning abilities of cleaners.

Innovation Solution

The apparatus employs a control method that adjusts the cleaning voltage of cleaners based on charging current differences, ensuring that the cleaning abilities of all cleaners are either the same or differentiated to maintain uniform contamination levels on charging rollers, using a common charging power supply and separate cleaning power supplies with the same polarity but varying voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a common charging power supply is used for multiple charging rollers, then device complexity is reduced, but charging current differences occur due to uneven contamination levels

Engineering Contradiction:

Improvecharging power supply configurationVSAvoidcharging current uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies different cleaning voltages to different cleaners based on their individual contamination levels. The control device adjusts the cleaning voltage for each cleaner independently according to the charging current difference detected for its corresponding charging roller, ensuring localized optimization of cleaning ability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the cleaning voltage parameter dynamically based on contamination levels. When contamination is detected (indicated by charging current differences), the cleaning voltage is adjusted to appropriate values to optimize cleaning ability. This parameter change allows the system to adapt to varying contamination conditions while using a common charging power supply.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If cleaning ability is increased for all cleaners, then contamination levels are reduced, but image quality may deteriorate due to excessive cleaning

Engineering Contradiction:

Improvecontamination controlVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies different cleaning voltages to different cleaners based on their individual contamination levels. The control device adjusts the cleaning voltage for each cleaner independently according to the charging current difference detected for its corresponding charging roller, ensuring localized optimization of cleaning ability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses appropriate cleaning voltages (not maximum values) to achieve sufficient cleaning. By selecting cleaning voltages from predetermined values based on contamination levels, the system applies just enough cleaning action needed, avoiding excessive cleaning that would deteriorate image quality.

Inventive Principle:

Principle #16Partial or excessive action

3Manufacturing precision

If different cleaning voltages are applied to different cleaners, then charging current differences are reduced, but device complexity increases

Engineering Contradiction:

Improvecharging current uniformityVSAvoidcleaning power supply configuration

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the cleaning voltage parameter dynamically based on contamination levels. When contamination is detected (indicated by charging current differences), the cleaning voltage is adjusted to appropriate values to optimize cleaning ability. This parameter change allows the system to adapt to varying contamination conditions while using a common charging power supply.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a single cleaning power supply that can output multiple different voltages to serve multiple cleaners with different contamination levels. This multi-functional approach allows one power supply to replace what would otherwise require multiple dedicated power supplies, reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If cleaning processing is performed frequently, then contamination levels are maintained uniformly, but productivity decreases

Engineering Contradiction:

Improvecontamination uniformityVSAvoidimage formation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where the control device detects charging current differences and uses this information to determine when cleaning is needed. By continuously monitoring the charging current and comparing it against reference values, the system triggers cleaning processing only when contamination levels warrant intervention, optimizing the balance between contamination control and productivity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs cleaning processing periodically based on detected contamination levels rather than continuously. The control device determines appropriate timing for cleaning based on charging current differences, creating a periodic cleaning schedule that maintains contamination uniformity while minimizing interruptions to image formation productivity.

Inventive Principle:

Principle #19Periodic 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 maintains uniform contamination levels on charging rollers, reduces current differences, and ensures consistent image quality by controlling the cleaning abilities of cleaners, simplifying the mechanical configuration and reducing operational costs.

Implementation Method 1

a charging power supply common to the first charging roller and the second charging roller and configured to apply a same charging voltage to the first charging roller and the second charging roller

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a cleaning power supply configured to apply a cleaning voltage which has a same polarity as the charging voltage and an absolute value larger than the charging voltage to the first cleaner and the second cleaner

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentUS10289019B2Image forming apparatus that controls cleaning ability of cleaner and control method thereof

Publication Date: 2019.05.14 BROTHER KOGYO KK

AI summary

An image forming apparatus configured to, in a case where a difference between a charging current flowing through a first charging roller and a charging current flowing through a second charging roller is larger than a first threshold value, perform first cleaning processing in which a cleaning ability of one cleaner of a first cleaner and a second cleaner, which corresponds to one of the first charging roller and the second charging roller, is lower than a cleaning ability of another cleaner of the first cleaner and the second cleaner, which corresponds to another of the first charging roller and the second charging roller, a charging current flowing through the one charging roller being larger than a charging current flowing through the other charging roller.