Conductive Intermediate Transfer Belt for Reverse Transfer Prevention
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Solution Overview
Problem
Conventional image forming apparatuses using intermediate transfer belts face issues with reverse transfer of toner images due to electric discharge at primary transfer sections, leading to image unevenness and reduced density, and existing solutions either fail to prevent reverse transfer or compromise primary transfer efficiency by adjusting voltage settings.
Innovation Solution
The use of a conductive intermediate transfer belt with a circumferential resistance of 10^4 to 10^8 Ω, which allows current to flow in the rotational direction to maintain a predetermined surface potential, enabling primary transfer without voltage application to primary transfer rollers and reducing the number of voltage power supplies, thereby preventing reverse transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If voltage is applied to primary transfer rollers to improve primary transfer efficiency, then transfer efficiency is improved, but reverse transfer occurs due to electric discharge
Solution Approach 1:
The patent introduces an intermediate transfer belt as a mediator between the photosensitive drum and the final transfer destination. The intermediate transfer belt with conductive properties (10^4 to 10^8 Ω) acts as a buffer that prevents direct electric discharge between high-voltage components, thereby eliminating reverse transfer while maintaining efficient primary transfer through the intermediate medium
Solution Approach 2:
The patent changes the electrical resistance parameter of the intermediate transfer belt to a specific range (10^4 to 10^8 Ω) that optimizes both primary transfer efficiency and reverse transfer prevention. This parameter change allows the intermediate belt to conduct sufficient current for efficient transfer while preventing the electric discharge that causes reverse transfer
2Object-generated harmful factors
If voltage is decreased at primary transfer sections to prevent reverse transfer, then reverse transfer is prevented, but primary transfer efficiency decreases
Solution Approach 1:
The patent segments the transfer process into two distinct stages: primary transfer from photosensitive drum to intermediate transfer belt, and secondary transfer from intermediate transfer belt to final destination. This segmentation allows independent optimization of each stage, enabling high voltage for efficient primary transfer while using the intermediate belt's conductive properties to prevent reverse transfer without compromising overall efficiency
Solution Approach 2:
The intermediate transfer belt serves as an intermediary that decouples the voltage requirements of primary and secondary transfer. It allows high voltage to be applied at the primary transfer stage for efficiency while its conductive properties prevent reverse transfer, eliminating the need to decrease voltage and thereby maintaining high primary transfer efficiency
3Measurement precision
If multiple voltage power supplies are used for each primary transfer roller, then transfer control precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the voltage control function into a single power supply that controls the intermediate transfer belt, eliminating the need for multiple separate voltage power supplies for each primary transfer roller. The intermediate belt's conductive properties enable it to distribute voltage uniformly, maintaining control precision while reducing device complexity through consolidation
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 effectively prevents reverse transfer while maintaining high primary transfer efficiency, ensuring stable image formation and reducing the complexity and cost of the image forming apparatus by eliminating the need for multiple voltage power supplies.
Implementation Method 1
an intermediate transfer belt with a circumferential resistance of 10^4 to 10^8 Ω, which allows current to flow in the rotational direction to maintain a predetermined surface potential
Implementation Method 2
a transferred toner image of the first color on the intermediate transfer belt is electrostatically attracted to the intermediate transfer belt
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An image forming apparatus sequentially transfers toner images formed on a plurality of photosensitive drums onto an intermediate transfer member or a transfer material to form an image. The image forming apparatus includes an intermediate transfer belt provided with electrical conductivity, and a power supply for applying a voltage to a current supply member contacting the intermediate transfer belt to pass a current from the current supply member to the plurality of photosensitive drums via the intermediate transfer belt, thus generating electric discharge on the upstream side of each of primary transfer sections.