Developing Roller Drive Gear Alignment for Stable Contact
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Solution Overview
Problem
Existing image forming apparatuses face instability in the contact condition and connecting/disconnecting operation of developing rollers with photosensitive drums due to the inclusion of rotational force components that affect the attaching/detaching direction, leading to potential wear and unstable contact.
Innovation Solution
The design incorporates a process cartridge with a developing cartridge that includes a developing roller drive gear and bearing members guided by attachment guide grooves, where the rotational moment generated by the drive gear ensures stable contact and a spacing member allows for proper spacing and movement of the developing roller relative to the photosensitive drum, ensuring alignment and force directionality for stable engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rotational force is inputted into the gear on the developing cartridge, then the developing roller can be rotated for image formation, but the rotational moment generated presses the bearing units against the receiving portions, causing unstable contact condition of the developing roller with the photosensitive drum
Solution Approach 1:
The patent extracts the disturbing rotational moment component by providing a rotational force input mechanism (gear motor with gear) that rotates the developing roller independently without generating destabilizing moments on the bearing units. The bearing units are designed to receive only axial guiding forces, separating the rotation function from the positioning function.
Solution Approach 2:
The patent segments the functions of the developing cartridge: the bearing units are responsible solely for guiding and positioning the developing roller axially, while the gear mechanism provides independent rotational drive. This functional segmentation prevents interference between positioning and rotation operations.
2Ease of operation
If the developing roller is connected to or disconnected from the photosensitive drum while rotational force is inputted into the gear, then the developing roller can be engaged or disengaged, but the force component in the attaching/detaching direction causes unstable connecting/disconnecting operation
Solution Approach 1:
The patent extracts the disturbing force component by designing the bearing units to receive only axial guiding forces during attachment/detachment operations. The rotational force input mechanism is designed to apply torque only to the developing roller shaft, not to the bearing units, eliminating the destabilizing force component in the attaching/detaching direction.
Solution Approach 2:
The patent implements preliminary guiding action through the guide grooves that align and guide the bearing units into the receiving portions before the developing roller makes contact with the photosensitive drum. This preliminary guiding ensures stable engagement without the interference of rotational forces.
3Duration of action of stationary object
If the developing roller is spaced apart from the photosensitive drum when no image is formed, then wear of the developing roller is suppressed, but the connecting/disconnecting operation becomes unstable due to rotational moment from the gear
Solution Approach 1:
The patent extracts the disturbing rotational moment by providing an independent rotational force input mechanism (gear motor with gear) that drives the developing roller without generating destabilizing moments on the bearing units during spacing operations. The bearing units are designed to receive only axial guiding forces, separating the spacing function from the rotation function.
Data Source
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AI summary
An image forming apparatus is provided. An image forming apparatus includes: a drum cartridge having a photosensitive drum; a developing cartridge configured to be movably attached to the drum cartridge, the developing cartridge having: a developing roller; a bearing member; and a developing drive input member; and a spacing member for pressing against a predetermined portion of the developing cartridge and moving the developing cartridge such that the developing roller is spaced apart from the photosensitive drum, wherein the drum cartridge has an abutment portion with which the bearing member is brought into abutment, and wherein a straight line which connects the abutment portion with a center of a rotational axis of the developing drive input member extends substantially in the same direction as a connecting or disconnecting direction of the developing roller to or from the photosensitive drum.