Cleaning Member Pressure and Photosensitive Layer Ionization Potential for Ghost Image Prevention
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Solution Overview
Problem
In electrophotographic image forming apparatuses, high-definition toner with small particle diameter and high roundness tends to pass through the gap between the cleaning member and the image bearing member, leading to insufficient cleaning, and applying high pressure to prevent this can cause damage to the image bearing member, while also potentially resulting in ghost images due to non-uniform charge injection.
Innovation Solution
The use of a cleaning member with a linear pressure of 10 N/m to 40 N/m on the image bearing member, combined with a single-layer photosensitive layer containing specific charge generating and hole transport materials that satisfy certain ionization potential conditions, to prevent ghost images and ensure effective toner collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cleaning member is tightly pressed against the image bearing member to prevent toner from passing through the gap, then cleaning effectiveness is improved, but friction force increases causing damage to the image bearing member
Solution Approach 1:
A lubricant is introduced as an intermediary substance between the cleaning member and the image bearing member. The lubricant application mechanism applies lubricant to the image bearing member upstream of the cleaning means, creating a lubricating layer that reduces friction force while allowing the cleaning member to maintain sufficient pressure for effective toner collection.
2Manufacturing precision
If high pressure is applied to prevent toner from passing through the gap, then cleaning effectiveness is improved, but ghost images may occur due to non-uniform charge injection
Solution Approach 1:
The lubricant acts as a mediator that decouples the relationship between cleaning pressure and friction. By reducing friction through lubrication, the cleaning member can operate at optimal pressure levels that ensure effective toner collection without excessive pressure that would cause non-uniform charge injection and ghost images.
3Manufacturing precision
If the gap between cleaning member and image bearing member is reduced to prevent toner passage, then cleaning effectiveness is improved, but friction force increases
Solution Approach 1:
The lubricant introduced between the cleaning member and image bearing member reduces the coefficient of friction, allowing the system to maintain a small gap for effective cleaning while keeping friction forces at acceptable levels. The lubricating layer enables smooth relative motion even with tight clearance.
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 solution effectively inhibits ghost image occurrence and ensures practical cleanability even with high-definition toners, while maintaining the integrity of the image bearing member, by optimizing the ionization potentials of the materials and pressure application.
Implementation Method 1
The single-layer photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin
Implementation Method 2
The cleaning member is pressed against a circumferential surface of the image bearing member and collects a toner remaining on the circumferential surface of the image bearing member
Data Source
AI summary
In an image forming apparatus, a cleaning member is pressed against a circumferential surface of an image bearing member and collects a toner remaining on the circumferential surface of the image bearing member. The toner has a number average roundness of 0.965 to 0.998. The toner has a D50 of 4.0 μm to 7.0 μm. A linear pressure of the cleaning member on the circumferential surface of the image bearing member is 10 N/m to 40 N/m. The image bearing member includes a single-layer photosensitive layer containing a charge generating material and a hole transport material. Ionization potential IpHTM of the hole transport material and ionization potential IpCGM of the charge generating material satisfy mathematical formula (1) “IpHTM≥5.30 eV”, mathematical formula (2) “IpCGM≥5.30 eV”, and mathematical formula (3) “0.09 eV≤|IpHTM−IpCGM|≤0.30 eV”.