Cleanerless Process Cartridge Toner Shape Integrity
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Solution Overview
Problem
In cleanerless electrophotographic systems, the formation of fogging images due to charging failures and contamination of charging members is not adequately addressed, especially when the outer diameter of the electrophotographic photosensitive member is 23 mm or less, leading to increased curvature and stress on toner particles, causing them to break and lose triboelectricity.
Innovation Solution
A process cartridge with an electrophotographic photosensitive member having a surface layer containing polyarylate or polycarbonate resin, and toner particles with specific size and shape characteristics (weight-average particle diameter of 7.1 μm to 10.0 μm, average circularity of 0.95 or more, and average aspect ratio of 0.90 or more) to reduce the proportion of odd-form toners that are prone to breaking and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer diameter of the electrophotographic photosensitive member is reduced to 23 mm or less for miniaturization, then the size of the electrophotographic apparatus is reduced, but the curvature and stress on toner particles increase causing them to break and lose triboelectricity
Solution Approach 1:
The patent changes the physical parameters of toner particles by specifying a weight-average particle diameter of 7.1 μm or more and 10.0 μm or less, along with minimum circularity and aspect ratio requirements. These parameter specifications ensure that toner particles maintain sufficient size and shape integrity even when used on small-diameter photosensitive members (23 mm or less), preventing particle breakage and preserving triboelectric properties necessary for reliable image formation in miniaturized electrophotographic systems.
2Device complexity
If a cleaning device is removed to implement a cleanerless system for miniaturization and ecology, then the device complexity is reduced, but charging failures and contamination of charging members occur leading to fogging images
Solution Approach 1:
The patent extracts the cleaning function from the electrophotographic system by removing the cleaning device entirely, implementing a cleanerless architecture. This extraction reduces device complexity and eliminates the need for cleaning mechanisms while maintaining reliable operation through optimized toner particle characteristics that prevent contamination and charging failures.
Solution Approach 2:
The patent enables the developing device to self-service by collecting residual toner left on the photosensitive member after transfer. The optimized toner particles (with specific size, circularity, and aspect ratio parameters) are designed to be easily collected by the developing device without requiring separate cleaning mechanisms, thus maintaining image quality and preventing fogging in a cleanerless system.
3Manufacturing precision
If toner particles with smaller size are used to improve resolution, then the manufacturing precision is improved, but the toner particles become more prone to breaking and losing triboelectricity
Solution Approach 1:
The patent optimizes toner particle parameters by specifying a weight-average particle diameter within 7.1 μm to 10.0 μm, along with minimum circularity (0.95 or more) and aspect ratio (0.90 or more). These parameter specifications balance manufacturing precision for high-resolution imaging with sufficient particle strength to prevent breakage and maintain triboelectric properties, resolving the contradiction between fine particle size and particle durability.
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 suppresses the formation of fogging images by reducing the proportion of odd-form toners, improving transfer efficiency and reducing charging failures, thereby enhancing the reliability of the cleanerless system.
Implementation Method 1
a charging device that charges the electrophotographic photosensitive member
Implementation Method 2
a developing device that forms a toner image on the electrophotographic photosensitive member through development using a toner
Implementation Method 3
transferring the toner image formed on the electrophotographic photosensitive member onto a transfer material
Data Source
AI summary
A process cartridge includes an electrophotographic photosensitive member, a charging device, and a developing device. The electrophotographic photosensitive member has a surface layer containing a polyarylate resin and a polycarbonate resin. The electrophotographic photosensitive member has an outer diameter of 23 mm or less and the developing device is configured to collect a residual toner left on the electrophotographic photosensitive member. A toner has a weight-average particle diameter (D4) of 7.1 μm or more and 10.0 μm or less, an average circularity of 0.95 or more, and an average aspect ratio of 0.90 or more.