Transfer Roller Bearing Layout for Stable Power Supply and Low Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image forming apparatuses face issues with energization failures and abnormal noise due to abrasion of electroconductive brushes or carbon chips, leading to degraded transfer properties such as image non-uniformity, as the shaft portion and bearing formed with electroconductive resin slide and abrade during operation.
Innovation Solution
The image forming apparatus employs a transfer roller with a rotatable roller portion and shaft portions supported by bearings, held by movable holding members with urging members to form a power supply path, ensuring stable power supply and reducing abrasion by positioning the contact member upstream of the rotation center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electroconductive brush or carbon chips is contacted to a shaft portion of the transfer roller to provide electrical connection, then the transfer roller can be electrically connected to a power supply path, but there is a possibility of an occurrence of energization failure due to abrasion of the electroconductive brush or carbon chips and an occurrence of abnormal noise due to sliding of metals with each other
Solution Approach 1:
A bearing made of electroconductive resin is introduced as an intermediary component between the shaft portion and the contact member. The bearing provides both mechanical support (reducing friction and wear) and electrical conduction, eliminating the need for direct metal-to-metal contact and preventing energization failures due to brush abrasion
Solution Approach 2:
The contact member is positioned upstream of the rotation center rather than at the rotation center or downstream. This parameter change in contact position reduces the sliding distance and wear between the contact member and bearing, while maintaining effective electrical connection and pressurization
2Reliability
If a bearing formed with an electroconductive resin is used to rotationally support a shaft portion and pressurization and electrical connection are made by an electroconductive spring, then electrical connection is achieved, but the shaft portion or the bearing is abraded due to sliding while being pressurized, so that there is a possibility that a set pressurizing force cannot be applied
Solution Approach 1:
The holding member acts as an intermediary structure that applies pressurization force to the bearing without requiring direct sliding contact between the shaft and pressurization mechanism. This separates the pressurization function from the rotational support function, preventing wear that would compromise pressurizing force
Solution Approach 2:
The patent replaces the conventional electroconductive spring pressurization system with a holding member structure that provides more stable and consistent pressurization. This mechanical substitution eliminates the wear and deformation issues associated with spring-based pressurization while maintaining electrical conductivity through the bearing
3Reliability
If the contact member is disposed at the rotation center or downstream side, then electrical connection is made, but the contact member is subjected to greater wear and may affect transfer properties
Solution Approach 1:
The contact member is deliberately positioned upstream of the rotation center rather than at the rotation center or downstream. This parameter change in contact position reduces the sliding distance and wear between the contact member and bearing, while maintaining effective electrical connection and minimizing impact on transfer properties
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 ensures stable power supply and reduces abrasion, maintaining consistent transfer properties and preventing image non-uniformity, while allowing easy assembly and disassembly of the transfer roller.
Implementation Method 1
a first urging member configured to urge the first holding member toward the image bearing member; a second urging member configured to urge the second holding member toward the image bearing member
Implementation Method 2
a contact member supported movably relative to the first holding member and provided so as to be contactable to an outer peripheral surface of the first bearing, wherein the contact member forms a power supply path to the transfer roller
Implementation Method 3
a first bearing mounted to the shaft portion at the one end portion; a second bearing mounted to the shaft portion at the other end portion
Data Source
AI summary
An image forming apparatus includes an image bearing member, a transfer roller, a first bearing, a second bearing, a first holding member, a second bearing member, a first urging member, a second urging member, and a contact member. With respect to a direction in which the first holding member is urged by the first urging member, the contact member contacts the first bearing on a side upstream of a rotation center of the transfer roller so as not to be disposed on a side downstream of the rotation center of the transfer roller.