Primary Transfer Roller Overlap for Stable Toner Transfer
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face issues with toner splashing and discharge craters due to the offset positioning of the primary transfer roller relative to the photoconductor drum, leading to image defects like banding and reduced mechanical service life.
Innovation Solution
The apparatus is designed with a primary transfer roller that intrudes into the photoconductor drum via the intermediate transfer belt, ensuring a stable overlap and pressure at the nip region, maintaining transfer performance and extending the mechanical life of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the primary transfer roller is offset to the downstream side with respect to the photoconductor drum, then the intermediate transfer belt can be made to move in contact with the photoconductor drum, but toner splashing and discharge craters occur leading to image defects
Solution Approach 1:
The patent introduces a new spatial dimension by allowing the primary transfer roller to intrude into the photoconductor drum in the radial direction while maintaining downstream offset in the tangential direction. This three-dimensional positioning creates a stable contact region where the roller axis extends beyond the drum surface, enabling proper belt contact without toner splashing or discharge craters.
Solution Approach 2:
The patent applies different positional characteristics to different regions: the primary transfer roller has downstream offset at its centerline but intrudes radially to create local contact stability. The intermediate transfer belt has variable tension along its path, with increased tension in the contact region to maintain stable engagement. This localized optimization prevents harmful effects while preserving operational functionality.
2Ease of operation
If the primary transfer roller is offset to the downstream side, then the contact region can be established, but the mechanical service life of components is reduced
Solution Approach 1:
The patent implements beforehand cushioning by designing the intermediate transfer belt with pre-tensioning and elasticity to compensate for the offset positioning. The belt's elastic properties allow it to absorb mechanical stresses and vibrations generated by the downstream offset contact, preventing excessive wear on the photoconductor drum and primary transfer roller, thereby extending component service life.
Solution Approach 2:
The patent optimizes multiple parameters including the intrusion depth of the primary transfer roller (0.1-2.0mm), the offset distance (1.0-5.0mm), and the belt tension (10-50N) to achieve the optimal balance between contact stability and mechanical durability. These parameter adjustments ensure stable toner transfer while minimizing mechanical stress on components.
3Stability of the object's composition
If the summit of the primary transfer roller intrudes on the photoconductor drum, then transfer pressure is stabilized, but the device complexity increases
Solution Approach 1:
The patent implements self-service by using the elasticity and tension of the intermediate transfer belt itself to maintain stable contact and transfer pressure. The belt's mechanical properties automatically adjust to compensate for the intrusion and offset positioning, eliminating the need for complex external pressure control mechanisms or adjustment devices.
Solution Approach 2:
The patent applies dynamics by allowing the intermediate transfer belt to have variable tension along its path, with increased tension in the contact region. This dynamic tension distribution enables the system to automatically adapt to the downstream offset and intrusion geometry, maintaining stable transfer pressure without rigid positioning mechanisms.
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 transfer pressure, prevents image defects, and prolongs the service life of the photoconductor drum and intermediate transfer belt by optimizing the overlap and intrusion of the primary transfer roller.
Implementation Method 1
presses the intermediate transfer belt against the photoconductor drum, thereby transferring the toner image
Implementation Method 2
carries an electrostatic latent image, which is developed into a toner image by application of toner
Data Source
AI summary
An image forming apparatus includes a photoconductor drum, an intermediate transfer belt that moves in contact with the photoconductor drum, and a primary transfer roller that transfers a toner image on the photoconductor drum, to the intermediate transfer belt. A part of a first contact region between the intermediate transfer belt and the photoconductor drum, and a part of a second contact region between the intermediate transfer belt and the primary transfer roller, are made to overlap. A summit of the primary transfer roller, closest to the photoconductor drum in a direction in which the photoconductor drum and the primary transfer roller are aligned across the intermediate transfer belt, is set to intrude on the photoconductor drum, via the intermediate transfer belt. An intrusion amount of the summit of the primary transfer roller on the photoconductor drum, relative to an overlapping amount, is set within a predetermined proper range.