Transfer Device Roller Spacing Asymmetry
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Solution Overview
Problem
Conventional transfer devices in image forming apparatuses face challenges in downsizing due to collisions between transfer members and rollers when reducing the spacing between rollers, which affects the moving direction of the intermediate transfer belt.
Innovation Solution
The transfer device incorporates a transfer member moving mechanism that adjusts the position of transfer members relative to the image bearing members, with the most upstream and downstream transfer members' rotational axes positioned downstream and upstream of the corresponding image bearing members' axes, respectively, allowing for reduced roller spacing without collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the spacing between first and second entraining rollers is reduced to downsize the transfer device, then the device size is reduced, but transfer members may collide with the rollers
Solution Approach 1:
The patent applies asymmetry by positioning the rotational axes of transfer members at different locations relative to image bearing members. Specifically, the most upstream transfer member has its rotational axis positioned downstream from the upstream image bearing member, while the most downstream transfer member has its rotational axis positioned upstream from the downstream image bearing member. This asymmetric arrangement creates clearance between transfer members and entraining rollers, allowing reduced roller spacing without collisions.
Solution Approach 2:
The patent resolves the collision issue by utilizing the longitudinal dimension (along the moving direction of the intermediate transfer belt) to position rotational axes, rather than only adjusting lateral spacing. By shifting rotational axes upstream or downstream in the moving direction, the patent creates sufficient clearance between transfer members and rollers even when roller spacing is reduced, effectively using an additional spatial dimension to solve the contradiction.
2Device complexity
If all transfer members are offset downstream from image bearing members, then the transfer device can be simplified, but the spacing between transfer members and rollers is reduced
Solution Approach 1:
The patent breaks the conventional symmetric arrangement where all transfer members are offset in the same direction. Instead, it employs asymmetric positioning: upstream transfer members are offset downstream while downstream transfer members are offset upstream. This asymmetric configuration maintains structural simplicity while increasing the effective spacing between transfer members and rollers, allowing for device downsizing.
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 enables the transfer device and image forming apparatus to be downsized in the moving direction of the intermediate transfer belt while maintaining effective image transfer and avoiding collisions with rollers.
Implementation Method 1
The plurality of transfer members are opposed to the respective image bearing members across the intermediate transfer belt for performing the primary transfer of the developer images born on the respective image bearing members onto the intermediate transfer belt when the transfer members are applied with voltage.
Data Source
AI summary
A transfer device includes an intermediate transfer belt, and a plurality of intermediate transfer rollers. A most upstream side intermediate transfer roller which is located most upstream in a moving direction of the intermediate transfer belt has a rotational axis arranged downstream from a rotational axis of a most upstream side photoreceptor drum which is located most upstream in the moving direction of the intermediate transfer belt when the most upstream side intermediate transfer roller is in its pressing position, while a most downstream side intermediate transfer roller which is located most downstream in the moving direction of the intermediate transfer belt has a rotational axis arranged upstream from a rotational axis of a most downstream side photoreceptor drum which is located most downstream in the moving direction of the intermediate transfer belt when the most downstream side intermediate transfer roller is in its pressing position.