Photosensitive Drum Gear Synchronization via Pitch Compensation
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Solution Overview
Problem
Image formation failures occur due to mismatched circumferential speeds of photosensitive drums in image forming apparatuses, often caused by dimensional unevenness in gears, leading to issues like color deviation and print quality deterioration.
Innovation Solution
The image forming apparatus employs a gear transmission mechanism where the first and second photosensitive drums have the same diameter, with specific tooth positions and shift angles to ensure synchronized rotational forces, maintaining consistent circumferential speeds during exposure and transfer, thereby reducing the impact of gear dimensional unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single drive source is used to drive multiple photosensitive drums via intermediate gears, then device complexity is reduced and cost is lowered, but dimensional unevenness of the gears causes circumferential speed variations leading to color deviation and image quality deterioration
Solution Approach 1:
The patent changes the geometric parameters of the gears, specifically setting the reference pitch circle radius and reference pitch at critical positions (exposure and transfer) to specific values that compensate for dimensional unevenness. This ensures that the circumferential speed at these critical positions remains consistent across all photosensitive drums, thereby resolving the speed consistency issue while maintaining the simple single-drive configuration
Solution Approach 2:
The patent performs preliminary design and calculation of gear parameters before manufacturing. By pre-calculating the reference pitch circle radius and reference pitch at exposure and transfer positions to satisfy specific mathematical relationships, the system proactively compensates for potential dimensional variations, ensuring consistent circumferential speed without requiring complex real-time control mechanisms
2Manufacturing precision
If multiple drive motors are used for each photosensitive drum, then circumferential speed consistency is improved, but device complexity, cost, and size increase
Solution Approach 1:
Instead of using multiple drive motors, the patent changes the gear parameters (reference pitch circle radius and reference pitch) at critical positions to compensate for dimensional unevenness. This mathematical compensation approach achieves circumferential speed consistency while maintaining the simplicity of a single drive source, thereby avoiding the complexity and cost of multiple motors
3Ease of manufacture
If gear dimensional unevenness is present, then manufacturing ease is improved, but circumferential speed varies causing color splippage and image formation failure
Solution Approach 1:
The patent identifies critical positions (exposure and transfer) and sets specific parameter values at these positions that make the system less sensitive to dimensional variations. By optimizing the reference pitch circle radius and reference pitch at these critical points, the patent ensures reliable image formation even when general gear dimensional unevenness exists, thereby maintaining both ease of manufacture and image formation reliability
Solution Approach 2:
The patent converts the harmful effect of gear dimensional unevenness into a benefit by designing the gear parameters such that the unevenness naturally compensates for itself at critical positions. The dimensional variations that would normally cause color splippage are mathematically compensated through careful selection of reference parameters, turning a manufacturing imperfection into a tolerance-friendly design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures that the circumferential speed variations at exposure and transfer positions are matched, inhibiting image formation failures even with gear dimensional unevenness, resulting in improved print quality by synchronizing the circumferential speed variations across all photosensitive drums.
Implementation Method 1
a first drum gear configured to apply a rotational force to the first photosensitive drum, a second drum gear configured to apply a rotational force to the second photosensitive drum
Data Source
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AI summary
An image forming apparatus includes gears for driving a first photosensitive drum and a second photosensitive drum. The gears includes a first drum gear, a second drum gear, and a first drive gear configured to apply a rotational force to the first drum gear and the second drum gear by meshing with the first drum gear and the second drum gear. Specific positional relations among the first photosensitive drum, the second photosensitive drum, the first drum gear, the second drum gear, and the first drive gear are configured based on exposure positions and transfer position. Such an image forming apparatus may reduce an occurrence of an image formation failure even when the dimensional unevenness of the gears occurs.