Magnetic Brush Cleaning for Photoconductor Drum
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Solution Overview
Problem
Image forming apparatuses face challenges in effectively cleaning the surface of photoconductor drums due to residual toner and discharge products, leading to reduced image quality and potential wear of cleaning blades, while existing magnetic brush systems may leave external additives on the drum surface, affecting toner development.
Innovation Solution
The apparatus supplies a greater amount of developer to the developing gap during non-image formation by adjusting the magnetic field strength, using a stronger magnetic field to enhance the cleaning process, ensuring effective removal of deposits and additives from the photoconductor drum surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blade member is used to clean the photoconductor drum surface, then residual toner and discharge products are removed, but cleaning blades wear out and require replacement
Solution Approach 1:
The developer material serves a dual function: it performs both image development and cleaning of the photoconductor drum surface. The developer automatically removes residual toner and discharge products during the development process itself, eliminating the need for separate cleaning blades and extending maintenance intervals
Solution Approach 2:
The invention changes the magnetic field strength parameter dynamically - using a first magnetic field strength during image formation for normal development, and a second, stronger magnetic field strength during non-image formation to supply excessive developer for enhanced cleaning action, thereby improving cleaning effectiveness without continuous blade wear
2Reliability
If a magnetic brush forming portion is used to remove discharge products, then cleaning is enhanced, but external additives remain on the drum surface affecting toner development
Solution Approach 1:
The invention applies periodic action by alternating between two operational modes: during image formation, normal magnetic field strength is applied for toner development; during non-image formation (idle periods), a stronger magnetic field is applied to supply excessive developer that thoroughly cleans the drum surface by removing both discharge products and external additives, thereby preventing additive accumulation that would affect subsequent development quality
Solution Approach 2:
By dynamically changing the magnetic field strength parameter between two levels based on operational mode (image formation vs. idle), the system achieves thorough cleaning during idle periods without compromising normal development during image formation, eliminating the residual additive problem
3Reliability
If more developer is supplied to the developing gap, then cleaning effectiveness is improved, but developer consumption increases
Solution Approach 1:
The invention implements periodic action by supplying excessive developer only during non-image formation periods when cleaning is needed, while returning to normal developer supply during image formation periods. This time-based differentiation achieves effective cleaning without continuous excessive developer consumption
Solution Approach 2:
The magnetic field strength parameter is changed dynamically - increased during idle periods to promote excessive developer supply for cleaning, then reduced during image formation to restore normal developer consumption levels, thereby resolving the contradiction between cleaning effectiveness and material consumption
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 effectively removes residual toner, external additives, and discharge products, maintaining image quality and extending the life of cleaning blades by ensuring thorough cleaning of the photoconductor drum surface.
Implementation Method 1
The magnetic force generating portion is provided in an inside of the developing roller and generates a magnetic force for keeping the developer on an outer circumferential surface of the developing roller
Implementation Method 2
toner is supplied from the developing roller to the electrostatic latent image on the photoconductor drum by an electric field generated by a developing bias applied to the developing roller
Implementation Method 3
the image carrying member is disposed to face the developing roller across a predetermined developing gap, is rotationally driven, receives the toner from the developer supplied to the developing gap by the developing roller, and keeps a toner image on an outer circumferential surface of the image carrying member
Data Source
AI summary
An image forming apparatus includes a developer storage portion, a developing roller, a magnetic force generating portion, and an image carrying member. The magnetic force generating portion is provided in the developing roller and generates a magnetic force for keeping the developer on an outer circumferential surface of the developing roller. The image carrying member is disposed to face the developing roller across a predetermined developing gap, is rotationally driven, receives the toner from the developer supplied to the developing gap by the developing roller, and keeps a toner image on an outer circumferential surface of the image carrying member. The image forming apparatus, during non image formation, supplies a more amount of developer to the developing gap than an amount of developer for developing supplied to the developing gap during image formation such that the outer circumferential surface of the image carrying member is cleaned.