Gear Train Phase Offset for Motor Non-Uniformity in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face issues with rotation non-uniformity of a single motor affecting image quality, as the influence on the feeding belt is not adequately suppressed, leading to adverse effects on the image formed.
Innovation Solution
The apparatus incorporates a gear train system where the motor's driving force is transmitted to both the photosensitive member and the developing image receiving member, with a specific gear engagement phase difference and rotation amount to minimize the impact of motor non-uniformity, ensuring the photosensitive drum and the developing image receiving member are aligned to cancel out rotation speed fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor is used to drive both the photosensitive member and the developing image receiving member, then the device complexity is reduced, but the rotation non-uniformity of the motor adversely affects the image quality
Solution Approach 1:
The patent introduces a gear train as an intermediary mechanism between the motor and the driven components. The gear train includes a first gear engaged with the motor shaft, a second gear engaged with the first gear to drive the photosensitive member, and a third gear engaged with the first gear to drive the moving member. This intermediary gear system allows the motor to drive multiple components while the gear engagement phases can be controlled to cancel out rotation non-uniformity effects.
Solution Approach 2:
The patent changes the parameter of rotation amount by specifying that the motor rotates by 2πn+η radians when the photosensitive member rotates from the exposure position to the transfer position. The increased rotation amount η is specifically designed to compensate for the phase difference Φ between the gear engagements, thereby canceling the adverse effects of motor rotation non-uniformity on image quality.
2Manufacturing precision
If the motor rotation amount is increased by 2πn+η radians, then the rotation non-uniformity influence is suppressed, but the device requires precise control of the gear engagement phase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-setting the gear engagement phase difference Φ and the increased rotation amount η before the image formation process begins. The gear train is designed with specific engagement phases, and the motor control is programmed to rotate by the predetermined amount 2πn+η radians, thereby proactively compensating for rotation non-uniformity rather than correcting it during operation.
Solution Approach 2:
The patent implements feedback by monitoring the actual rotation of the photosensitive member and adjusting the motor rotation amount accordingly. The control system ensures that the motor rotates by the precise amount 2πn+η radians based on the phase difference Φ between gear engagements, creating a closed-loop control mechanism that maintains image quality despite motor non-uniformity.
3Manufacturing precision
If the gear engagement phase difference is utilized to cancel rotation non-uniformity, then the pitch fluctuation is reduced, but the gear train design becomes more complex
Solution Approach 1:
The patent merges the drive functions by using a single motor to drive both the photosensitive member and the moving member through a shared gear train. The first gear serves as a common intermediary that engages with both the second gear (for the photosensitive member) and the third gear (for the moving member), combining multiple drive functions into a unified system that leverages the phase difference Φ to cancel rotation non-uniformity.
Solution Approach 2:
The patent applies asymmetry by introducing a specific phase difference Φ between the engagement of the first gear with the second gear and the third gear. This asymmetric arrangement, where the engagement phases are deliberately offset, creates the conditions necessary for the rotation non-uniformity cancellation effect. The asymmetric gear train design is specifically configured so that the phase difference Φ, combined with the motor rotation amount 2πn+η, results in the cancellation of pitch fluctuations.
Data Source
AI summary
An image forming apparatus includes a photosensitive member; a charging member, an exposure member, a developing member, a transfer member, a moving member, a motor, a first drive transmitting portion, and a second drive transmitting portion. A rotation amount of the motor when the photosensitive member rotates from an exposure position to a transfer position during image formation is 2πn+η [rad] where n is a natural number, and η is an increased rotation amount [rad] of the motor. The following relationship is satisfied: 0<η<π−Φ where Φ is an angle [rad] which is formed by a line connecting rotation centers of a first gear of the motor and a second gear of the first driving transmitting portion and a line connecting rotation centers of the first gear of the motor and a third gear of the second driving transmitting portion.