Segmented Transfer Roller Bearing for Electrical Isolation
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Solution Overview
Problem
The existing electrophotographic image forming apparatuses face challenges in downsizing the rolling bearing and slider due to the need for electrical isolation, which complicates the compact configuration of the transfer device.
Innovation Solution
A transfer device is designed with a conductive section around the rotational shaft of the transfer roller to receive electricity from an external power supply and an insulated section to cover the image-carrying body, allowing for a compact configuration by separating the conductive and insulated sections radially and preventing electrical discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rolling bearing is provided to cover the outer circumferential surface of the rotational shaft, then the rotational shaft can be supported, but the bearing size increases in the radial direction due to the need for electrical isolation
Solution Approach 1:
The bearing is segmented into a conductive section and an insulated section that are radially separated. The conductive section contacts the rotational shaft to provide electrical connection, while the insulated section covers the image-carrying body to prevent discharge. This segmentation allows both electrical isolation and compact size without requiring a fully covered bearing.
Solution Approach 2:
Different sections of the bearing have different electrical properties: the conductive section provides electrical connection where needed, while the insulated section provides electrical isolation where needed. This local differentiation of properties allows the bearing to fulfill multiple functions within a compact structure.
2Reliability
If a slider is provided to cover the outer circumferential surface of the rolling bearing for electrical isolation, then discharge is prevented, but the device complexity increases and downsizing becomes difficult
Solution Approach 1:
The electrical isolation function that was previously separate (slider) is merged into the bearing structure itself. The insulated section of the bearing directly covers the image-carrying body, eliminating the need for a separate slider component and simplifying the overall structure.
Solution Approach 2:
The bearing is designed to perform multiple functions simultaneously: mechanical support of the rotational shaft, electrical connection via the conductive section, and electrical isolation via the insulated section. This multi-functionality eliminates the need for separate components like the slider.
3Volume of moving object
If the conductive section and insulated section are disposed to not overlap in radial direction, then the bearing can be downsized, but the manufacturing precision requirements increase
Solution Approach 1:
The bearing is segmented into radially separated conductive and insulated sections, allowing compact arrangement. The segmentation is designed with clear radial boundaries that can be manufactured using standard precision machining techniques, balancing compact size with manufacturability.
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 a compact bearing setup, allowing for precise positioning and efficient electrical supply to the transfer roller, thereby downsizing the bearing and improving the overall apparatus design.
Implementation Method 1
a conductive section (46) formed of conductive material, the conductive section being disposed in a position around the rotational shaft (41) of the transfer roller (9), the conductive section being configured to bear the rotational shaft (41) from an opposite side of the image-carrying body (3) with respect to the rotational shaft (41) and to be supplied with electricity from an external power supply
Implementation Method 2
an insulated section (58) formed of insulating material, the insulated section being disposed in a position around the rotational shaft (41), the insulated section being configured to cover the image-carrying body (3) from a side of the image-carrying body (3)
Data Source
AI summary
A transfer device is provided, which includes a transfer roller that is provided with a conductive rotational shaft, opposed to an external image-carrying body, and configured to transfer onto an image-transferred member a developer image carried by the image-carrying body, and a bearing rotatably supporting the rotational shaft of the transfer roller, the bearing including a conductive section that is disposed in a position around the rotational shaft of the transfer roller and configured to bear the rotational shaft from an opposite side of the image-carrying body with respect to the rotational shaft and to be supplied with electricity from an external power supply, and an insulated section that is disposed in a position around the rotational shaft and configured to cover the image-carrying body from a side of the image-carrying body.