Primary Transfer Roller Layout for Stable Toner Belt Transfer
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face issues with toner splashing and discharge craters due to the primary transfer roller being offset downstream from the photoconductor drum, leading to unstable toner transfer and potential image defects like banding and drum ghosts.
Innovation Solution
The apparatus adjusts the positional relationship between the photoconductor drum and primary transfer roller by overlapping contact regions and allowing the primary transfer roller summit to intrude into the drum via the intermediate transfer belt, maintaining stable pressure and transfer performance without increasing mechanical load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the primary transfer roller is offset downstream from the photoconductor drum, then the toner transfer can be performed, but toner splashing and discharge craters occur leading to image defects
Solution Approach 1:
The patent transitions from a conventional side-by-side arrangement to a stacked configuration where the primary transfer roller is positioned above the photoconductor drum. This spatial reconfiguration in the vertical dimension eliminates toner splashing and discharge craters while maintaining effective toner transfer through the intermediate transfer belt.
Solution Approach 2:
The intermediate transfer belt serves as a mediator between the photoconductor drum and the primary transfer roller. It receives the toner image from the drum and transfers it to the final medium, enabling the rollers to be positioned optimally without direct contact, thus preventing toner splashing while maintaining transfer efficiency.
2Device complexity
If the primary transfer roller is offset downstream, then the configuration is simpler, but banding and drum ghosts appear due to unstable toner transfer
Solution Approach 1:
By repositioning the primary transfer roller in the vertical dimension (stacked configuration) rather than offsetting it horizontally, the patent achieves stable toner transfer without banding and drum ghosts while maintaining configuration simplicity.
Solution Approach 2:
The intermediate transfer belt acts as a mediator that ensures stable toner transfer between the photoconductor drum and primary transfer roller, eliminating banding and drum ghosts while allowing for a simple stacked configuration.
3Productivity
If the primary transfer roller presses the intermediate transfer belt against the photoconductor drum, then toner transfer is achieved, but mechanical load increases reducing service life
Solution Approach 1:
The intermediate transfer belt serves as a mediator that distributes the pressing force from the primary transfer roller across a larger area of the photoconductor drum. This force distribution reduces mechanical stress concentration, maintaining toner transfer efficiency while extending the service life of the drum and belt.
Solution Approach 2:
The intermediate transfer belt, as a flexible thin film, conforms to the photoconductor drum surface and distributes the pressing force evenly across the contact area. This flexibility allows effective toner transfer with reduced peak mechanical loads, thereby extending component service life.
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 configuration stabilizes toner transfer, reduces image defects, and prolongs the mechanical service life of the photoconductor drum and intermediate transfer belt by ensuring consistent pressure and efficient transfer without excessive mechanical stress.
Implementation Method 1
The intermediate transfer belt is made to move in contact with the photoconductor drum. The primary transfer roller is opposed to the photoconductor drum via the intermediate transfer belt, and presses the intermediate transfer belt against the photoconductor drum, thereby transferring the toner image
Data Source
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AI summary
An image forming apparatus (1) includes a photoconductor drum (4), an intermediate transfer belt (5) that moves in contact with the photoconductor drum (4), and a primary transfer roller (31) that transfers a toner image on the photoconductor drum (4), therefrom to the intermediate transfer belt (5). A part of a first contact region (4S) between the intermediate transfer belt (5) and the photoconductor drum (4), and a part of a second contact region (1S) between the intermediate transfer belt (5) and the primary transfer roller (31), are made to overlap with each other. A summit of the primary transfer roller (31), closest to the photoconductor drum (4) in a direction in which the photoconductor drum (4) and the primary transfer roller (31) are aligned across the intermediate transfer belt (5), is set to intrude on the photoconductor drum (4), via the intermediate transfer belt (5). An intrusion amount (Kr) of the summit of the primary transfer roller (31) on the photoconductor drum (4), relative to an overlapping amount, is set within a predetermined proper range.