Cleaning Device Work Function Difference Toner Removal
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Solution Overview
Problem
Conventional cleaning devices struggle to effectively remove residual toner from electrophotographic photosensitive members, especially with small particle diameter toners and highly charged toners, leading to image defects due to insufficient charge elimination and electrostatic adhesion.
Innovation Solution
A cleaning device with a cleaning frame, a flexible sheet member, and a charging member that applies an AC voltage, where the work function difference between the toner and the sheet member is within a specific range (0≤W(D)−W(S)≤0.23), ensuring efficient toner removal without increasing the size or cost of the image forming apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional elastic blade cleaning device is used, then the structure is simple and cost is low, but small particle diameter toner fails to be sufficiently removed and faulty cleaning occurs due to increased slipping
Solution Approach 1:
The cleaning device is divided into two functional segments: a charging device that eliminates charge from residual toner and a cleaning blade that physically removes the toner. This segmentation allows each component to specialize in its function, with the charging device preparing the toner for easier removal and the cleaning blade executing the physical cleaning, thereby resolving the contradiction between simple structure and effective small particle toner removal
Solution Approach 2:
The charging device performs a preliminary action by eliminating the electrostatic charge from residual toner before the cleaning blade attempts physical removal. This preliminary charge elimination reduces the adhesion force between toner and photosensitive member, making subsequent mechanical removal by the cleaning blade more effective, especially for small particle diameter toner that would otherwise slip
2Reliability
If a charging device is added to eliminate charge of residual toner, then charge elimination is improved, but the apparatus size increases due to high-voltage output device requirements
Solution Approach 1:
The charging device is merged with the cleaning device structure, integrating the charge elimination function into the existing cleaning mechanism. This combination allows the charging function to be performed using the same space and structural framework as the cleaning blade assembly, avoiding the need for separate high-voltage output devices and thereby preventing significant increases in apparatus size while maintaining effective charge elimination
3Reliability
If a charging device is added to eliminate charge of residual toner, then charge elimination is improved, but the apparatus cost increases
Solution Approach 1:
The charging device is integrated with the cleaning blade assembly, combining two functions (charge elimination and mechanical cleaning) into a single unified structure. This merging eliminates the need for separate high-voltage power supplies and control systems that would be required for a standalone charging device, thereby reducing overall apparatus cost while maintaining effective charge elimination capability
Solution Approach 2:
The cleaning blade structure itself is utilized to perform the charging function by incorporating charging members that can eliminate charge from toner during the normal cleaning operation. This self-service approach allows the existing cleaning mechanism to dual-function as both a mechanical remover and a charge eliminator, avoiding additional cost investments in separate charging systems
4Manufacturing precision
If polymerized toner of high circularity is used, then image quality is improved, but scraping by cleaning blade becomes difficult and toner slips leading to image defects
Solution Approach 1:
The charging device performs a preliminary charge elimination action on the high circularity polymerized toner before the cleaning blade attempts mechanical removal. By eliminating the electrostatic charge that causes adhesion, the toner particles become easier to scrape off even though their high circularity makes them inherently difficult to remove, thereby maintaining both image quality and cleaning effectiveness
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 allows for effective removal of residual toner, reducing image defects and maintaining good image forming quality over time, even with small particle diameter or highly charged toners, in a compact and cost-effective configuration.
Implementation Method 1
a charging member, which is attached to the cleaning frame and which charges the image bearing member
Implementation Method 2
a sheet member having flexibility and having one end attached to the cleaning frame and the other end that comes into contact with the image bearing member at an upstream side of a contact position between the cleaning member and the image bearing member in a rotation direction of the image bearing member; wherein a work function W (D) of the developer and a work function W (S) of the sheet member satisfy Expression (A) below
Data Source
AI summary
A cleaning device, including: a cleaning frame; a cleaning member having one end and the other end, an image bearing member being capable of rotating and bearing a developer image formed of a developer so as to remove the developer remaining on the image bearing member after transfer of the developer image from the image bearing member; and a sheet member having flexibility and having one end and the other end; wherein a work function W (D) of the developer and a work function W (S) of the sheet member satisfy 0≤W(D)−W(S)≤0.23 and the developer includes inorganic particles, and at least one kind of the inorganic particles has an average primary particle diameter of 50 nm or larger.