Movable Transfer Member Spacing for Drum Wear Reduction
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Solution Overview
Problem
Conventional tandem-type electrophotographic image forming apparatuses face issues with the deterioration of image bearing members and transfer receiving members due to insufficient spacing during monochromatic image output, particularly when forming black images, leading to increased friction and potential damage.
Innovation Solution
An image forming apparatus design that includes a rotatable first image bearing member, a plurality of rotatable second image bearing members, an endless belt, and a supporting member that can move to either contact or retract the second transfer members, allowing for increased spacing between the second image bearing members and the belt, thereby reducing friction and deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If transfer members for Y, M and C are spaced from the drums during monochromatic image output, then the lifetime of drums and developing devices is extended, but the distance between the transfer receiving member and the drum for C cannot be increased sufficiently
Solution Approach 1:
The transfer members for Y, M and C are designed to be movable relative to the drums, allowing them to be dynamically positioned in a spaced state during monochromatic image output. This dynamic adjustment ensures sufficient distance between the transfer receiving member and the drum for C, preventing contact even when the transfer receiving member is in a waved state, thereby extending the lifetime of drums and developing devices.
2Length of stationary object
If a pushing-up roller is used to space the transfer receiving member from the drums, then the distance is sufficiently increased, but the number of parts increases and the apparatus is upsized
Solution Approach 1:
The transfer members for Y, M and C serve multiple functions: they act as transfer members during color image output and as spacing members during monochromatic image output. By moving these existing transfer members to a spaced position, the apparatus achieves sufficient distance between the transfer receiving member and the drums without requiring additional pushing-up rollers or other spacing mechanisms, thereby avoiding increased part count and apparatus size.
Data Source
AI summary
An image forming apparatus includes a first image bearing member; a plurality of second image bearing members; an endless belt opposing the first and second image bearing members; a driving roller; a supporting roller; a first transfer member opposing the first image bearing member; a plurality of second transfer members provided opposing the second image bearing members; and a supporting member for supporting the second transfer members. The supporting member is movable between a first position as a contact position and a second position as a spaced position. When image formation is effected in a state in which the supporting member is positioned in the first position, a nip between the first image bearing member and the belt member is positioned to be spaced from a rectilinear line connecting contact positions of the belt member with the second image bearing members.