Primary Transfer Roller Angle Configuration for Ozone Reduction
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Solution Overview
Problem
Existing color image forming apparatuses using electrophotography face issues with ozone emissions, increased size and cost due to corotron usage, and reduced transfer efficiency when using transfer rollers and auxiliary rollers, leading to image quality deterioration and high ozone emissions.
Innovation Solution
The image forming apparatus employs a primary transfer roller arranged downstream of the image carrier with a specific angle configuration to minimize pressure and ozone emissions, using a metallic roller setup with controlled voltage application to achieve stable toner transfer and high image quality, while optimizing the transfer nip time and electric field for efficient toner transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a corotron is used for transfer, then transfer performance is improved, but ozone emissions increase and device size increases
Solution Approach 1:
The patent replaces the corotron (electrical field-based transfer mechanism) with a mechanical roller-based transfer system. The transfer roller applies direct mechanical contact and pressure to the photosensitive element, eliminating the need for high-voltage electrical fields that generate ozone. This substitution maintains transfer performance while eliminating harmful ozone emissions.
Solution Approach 2:
The patent removes the corotron component from the system entirely and replaces it with a simpler roller mechanism. By extracting the harmful electrical field generation aspect while retaining the essential transfer function through mechanical means, the invention eliminates ozone emissions while preserving transfer performance.
2Reliability
If tension rollers are added to improve belt tension control, then transfer stability is improved, but device size and cost increase
Solution Approach 1:
The patent combines the tensioning function with the existing transfer roller structure. The transfer roller itself is designed to provide both the transfer function and the belt tensioning function, eliminating the need for separate tension rollers. This integration maintains transfer stability while reducing device size and component count.
Solution Approach 2:
The transfer roller is designed to perform multiple functions: it transfers toner, applies mechanical pressure, and tensions the belt. By making the transfer roller a multi-functional component, the patent eliminates the need for additional dedicated tension rollers, thereby reducing device complexity while maintaining transfer stability.
3Productivity
If transfer voltage is increased to improve transfer efficiency, then toner transfer is improved, but toner scattering increases
Solution Approach 1:
The patent replaces electrical field-based toner transfer with mechanical contact-based transfer. The transfer roller applies direct mechanical pressure and friction to transfer toner, eliminating the need for high voltages that cause toner scattering. This mechanical approach achieves high transfer efficiency while maintaining sharp image edges without scattering.
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 reduces ozone emissions, minimizes image defects, and achieves high image quality with reduced costs by stabilizing the transfer process and preventing toner scattering, resulting in improved transfer efficiency and sharper images.
Implementation Method 1
a voltage is supplied from an identical power supply, unevenness in speed of a belt is reduced. Thus, deterioration in image quality is prevented
Data Source
AI summary
A primary transfer unit includes transfer units for performing a toner transfer from image carriers onto a transfer belt. Each of the transfer units is formed with a metallic roller. The metallic roller is arranged so as to satisfy θ1<θ2, where an angle of the endless belt with respect to a tangent to the image carrier, on a side upstream of rotation of the endless belt to a transfer nip region where the image carrier and the endless belt are in contact is θ1, and an angle of the endless belt with respect to the tangent, on a side downstream of rotation of the endless belt to the transfer nip region is θ2.