Photosensitive Drum Coupling for Selective Belt Contact
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Solution Overview
Problem
Existing image forming apparatuses with a conveying belt in contact with multiple photosensitive members lead to uneven wear and maintenance issues, particularly when forming monochrome images, as the non-used photosensitive members remain in contact, causing registration problems.
Innovation Solution
An image forming apparatus with a mode setting unit, contacting/separating mechanism, and transmitting mechanism that allows selective coupling and decoupling of photosensitive drums from an endless belt, maintaining uniform spacing between drums based on printing mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If photosensitive members are constantly in contact with the conveying belt, then image formation operation is simplified, but unnecessary wear and deterioration of photosensitive members occurs
Solution Approach 1:
The patent applies the dynamics principle by making the contact between photosensitive drums and conveying belt variable rather than fixed. The contacting/separating mechanism dynamically adjusts the contact state based on printing mode: during color printing, all drums contact the belt for normal operation; during monochrome printing, color drums separate from the belt to prevent unnecessary wear. This dynamic adjustment resolves the contradiction between operational simplicity and drum longevity.
2Duration of action of stationary object
If color image-forming unit is separated from conveying belt during black image formation, then unnecessary wear of color drums is prevented, but fluctuations in gap between black and color image-forming parts occur
Solution Approach 1:
The patent introduces coupling members as intermediary elements that mediate between the photosensitive drums and the drive system. These coupling members maintain stable mechanical connections and spacing relationships even when drums are separated from the conveying belt. The coupling members ensure that the gap between black and color image-forming parts remains constant during mode switching, preventing registration fluctuations while allowing the color drums to separate from the belt.
3Duration of action of stationary object
If black image-forming part and color image-forming unit are operated independently, then wear of color drums is reduced, but it becomes difficult to maintain uniform interval between neighboring photosensitive members
Solution Approach 1:
The patent merges the black and color image-forming parts into a single integrated unit structure. This unified configuration ensures that all photosensitive drums maintain uniform spacing and consistent mechanical relationships, regardless of whether they are actively contacting the conveying belt or separated. The merged structure prevents independent operation that would cause gap fluctuations, while still allowing color drums to separate during monochrome printing to reduce wear.
4Ease of operation
If all photosensitive members remain in contact with conveying belt during monochrome printing, then operational simplicity is maintained, but color registration accuracy deteriorates due to increased wear
Solution Approach 1:
The patent implements dynamic contact control where photosensitive drums are selectively separated from the conveying belt based on printing mode. During monochrome printing, color drums separate from the belt, reducing wear and maintaining color registration accuracy. During color printing, all drums contact the belt for normal operation. This dynamic adjustment maintains reliability without significantly complicating operation.
Data Source
AI summary
In an image forming apparatus, a process frame is movable into and out of a main casing in a first direction. The process frame includes a first wall and a second wall spaced apart from the first wall in a second direction. A first cartridge is detachably mountable to the process frame in a third direction crossing the second direction. A first electrode protrudes from an outer surface of the first cartridge outwardly in the second direction. In a state where the first cartridge is mounted to the process frame, the first cartridge is positioned between the first wall and second wall of the process frame in the second direction and a portion of the first wall aligns with the first electrode in the third direction such that the portion of the first wall is overlapped with the first electrode as viewed in the third direction.