Developing Roller Spacing Mechanism for Image Uniformity
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Solution Overview
Problem
Conventional image forming apparatuses face issues with the deterioration of developing rollers and photosensitive drums due to prolonged contact, leading to non-uniform images and accelerated wear, and require additional space for movable members that impede downsizing.
Innovation Solution
A drawer member with a contacting and spacing mechanism is integrated into the image forming apparatus, allowing the developing roller and photosensitive drum to be contacted and spaced relative to each other, preventing unnecessary contact and reducing wear, while eliminating the need for additional space in the main assembly for movable members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developing roller is kept in contact with the photosensitive drum during operation, then the developing operation can be performed, but the elastic layer of the developing roller deforms over time causing nonuniformity in the image
Solution Approach 1:
The developing roller is designed to be movable between a contact position (for developing operation) and a spaced position (for preventing deformation). The roller can dynamically change its position based on operational requirements, allowing it to contact the photosensitive drum only when needed for image formation, thereby preventing elastic layer deformation and maintaining image uniformity.
2Stability of the object's composition
If the developing roller contacts the photosensitive drum during non-operational periods, then the components remain in position, but the developer is deposited on the photosensitive drum unnecessarily and deterioration is accelerated
Solution Approach 1:
The developing roller is designed to automatically move to a spaced position when the image forming operation is not being carried out. This dynamic positioning prevents unnecessary contact between the developing roller and photosensitive drum, thereby preventing developer deposition on the photosensitive drum and reducing accelerated deterioration of both components.
3Reliability
If a movable member is provided in the main assembly to space the developing roller from the photosensitive drum, then the developing roller can be spaced from the photosensitive drum, but additional space is required in the main assembly impeding downsizing
Solution Approach 1:
Instead of providing a movable member in the main assembly to space the developing roller from the photosensitive drum, the invention inverts the approach by making the developing roller itself movable. The developing roller is designed to move between contact and spaced positions relative to the photosensitive drum, eliminating the need for additional movable members in the main assembly and thereby reducing the overall apparatus size.
4Ease of operation
If the drawer member carries the process cartridge into the main assembly, then the cartridge exchange is enabled, but the movable member must be retracted to avoid interference with the drawer member movement
Solution Approach 1:
Instead of retracting a movable member from the main assembly to avoid interference with the drawer member, the invention makes the developing roller itself movable. The developing roller can move between contact and spaced positions independently of the drawer member movement, allowing the drawer member to carry the process cartridge into the main assembly without requiring retraction of other movable members.
Data Source
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AI summary
The present invention relates to a drawer (63X) usable with an image forming apparatus (100) for forming an image on a recording material (S), the image forming apparatus (100) including a main assembly, the drawer (63, 63X) being movable between (i) an inside position in which the drawer (63X) is inside the main assembly and (ii) an outside position in which the drawer (63, 63X) is outside the main assembly, the drawer (63, 63X) comprising: a first photosensitive drum; a first mounting portion; a first developing cartridge (60X) being detachably mounted to the first mounting portion, the first developing cartridge including a first developing roller and a first projection (61X), the first developing roller being configured to contact the first photosensitive drum; a first unit (80) configured to support the first developing cartridge, the first unit including a first cartridge support member (81) and a first urging member (82) urging the first cartridge support member, wherein in a state where (i) the drawer is in the outside position (ii) the first developing cartridge is in a first position above a first mounted position where the first developing cartridge is capable of image forming operation and (iii) the first projection is placed on the first cartridge support member, the first urging member urges the first cartridge support member so that the first developing cartridge is not mounted to the first mounted position only by its weight of the first developing cartridge.