Secondary Transfer Roller Separation Mechanism for Compact Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in reducing size and space due to complex configurations for separating secondary transfer rollers from intermediate transfer belts, leading to issues like curl and reduced adhesiveness, which result in abnormal image formation.
Innovation Solution
An image forming apparatus with a simplified contact separation configuration, utilizing a moving member with an acting portion to move the secondary transfer member opposite to the urging direction, allowing for contact and separation from the intermediate transfer belt, thereby reducing the size and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reciprocating rod and a horizontal rod are used as different members to separate the secondary transfer member and primary transfer member, then the contact separation function is achieved, but the device complexity increases and size cannot be reduced
Solution Approach 1:
The patent combines the reciprocating rod and horizontal rod into a single integrated moving member that performs both separation functions. The moving member includes a reciprocating portion that contacts the secondary transfer member and a horizontal portion that contacts the primary transfer member, both integrated into one component that moves simultaneously to separate both contact members from the intermediate transfer belt.
Solution Approach 2:
The moving member is designed as a multi-functional component that simultaneously serves as both the reciprocating rod for separating the secondary transfer member and the horizontal rod for separating the primary transfer member. This universal component performs multiple separation functions within a single structure, reducing overall device complexity.
2Reliability
If the secondary transfer roller is arranged offset on the upstream side to prevent abnormal discharge, then discharge prevention is achieved, but a tension nip area is created that causes curl and reduces adhesiveness
Solution Approach 1:
The patent implements a dynamic separation mechanism where the secondary transfer member is separated from the intermediate transfer belt during non-printing periods through the reciprocating motion of the moving member. This dynamic on-demand contact and separation prevents the intermediate transfer belt from developing curl and maintains its flatness, while still allowing the offset arrangement for discharge prevention during active printing.
3Force
If the pressing force of the secondary transfer roller is set high to enhance adhesiveness, then transfer effectiveness is improved, but curl occurs in the tension nip area causing image defects
Solution Approach 1:
The patent employs periodic contact and separation cycles where the secondary transfer member contacts the intermediate transfer belt only during printing operations and separates during non-printing periods. This periodic action allows high pressing force to be applied only when needed for effective transfer, while preventing cumulative curl formation that would occur with continuous high-pressure contact.
Data Source
AI summary
An image forming apparatus includes a lever configured to move a secondary transfer roller from an endless belt. The lever is arranged between a primary transfer surface of the endless belt, which opposes a plurality of image bearing members between an opposing roller and a stretching roller, and a surface opposing the primary transfer surface. The lever is engaged with the secondary transfer roller to separate the secondary transfer roller from the endless belt. Such a simple contact-separation configuration for the secondary transfer roller achieves reduction in size and space of the image forming apparatus.