Phase Adjusting Unit for Rotational Fluctuation in Image Forming Apparatus
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Solution Overview
Problem
Conventional color image forming apparatuses face challenges in accurately detecting and correcting rotational fluctuations of photoconductors due to environmental changes and belt characteristics, leading to color unevenness and out-of-color registration issues.
Innovation Solution
An image forming apparatus with a plurality of image carriers, where each carrier is rotationally driven individually, and a phase adjusting unit adjusts the rotational fluctuation phase of one carrier based on a reference rotation position, ensuring precise phase matching across all carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotation detector including four slits is arranged on a shaft of the photoconductor to adjust the reference clock cycle, then the rotational fluctuation can be corrected, but the rotational fluctuation cannot be sufficiently removed, causing out-of-color registration
Solution Approach 1:
The patent replaces the mechanical four-slit rotation detector with an optical encoder that uses light reflection and detection. The encoder includes a scale plate with刻度 lines and a light source with photodetectors that measure positional deviations optically, eliminating the limitations of mechanical detection and achieving higher precision in rotational fluctuation measurement.
Solution Approach 2:
The patent uses resist marks (test patterns) transferred onto a transfer member as toner images to create a reference for detecting rotational fluctuations. By comparing the actual positions of these copied marks with their expected positions, the system can accurately measure rotational deviations and adjust accordingly.
2Measurement precision
If one encoder is coupled with a plurality of photoconductors to detect fluctuations, then phases of rotational fluctuation can be adjusted, but the mechanism becomes complicated and large
Solution Approach 1:
The patent divides the detection system into separate, independent encoder units for each photoconductor. Instead of coupling one encoder with multiple photoconductors, each photoconductor has its own encoder that independently detects its rotational fluctuations, simplifying the overall mechanism while maintaining detection accuracy.
Solution Approach 2:
The patent introduces a central control unit that acts as an intermediary, receiving detection signals from multiple independent encoders and coordinating the phase adjustments. This centralized control simplifies the coupling mechanism by eliminating direct mechanical connections between encoders and photoconductors, using electrical signals as intermediaries instead.
3Productivity
If belt transfer is used to transfer toner images, then the transfer process can be completed, but the fluctuation is affected by belt expansion and contraction
Solution Approach 1:
The patent performs preliminary detection of rotational fluctuations using encoders before the belt transfer process begins. By detecting and compensating for rotational deviations in advance, the system can account for belt expansion and contraction effects, ensuring accurate color registration even during the transfer process.
Solution Approach 2:
The patent implements a feedback mechanism where the encoder continuously monitors rotational position during the transfer process, and the control unit adjusts the photoconductor rotation in real-time based on detected deviations. This closed-loop feedback compensates for belt expansion and contraction, maintaining detection reliability throughout the transfer process.
Data Source
AI summary
An image forming apparatus includes a plurality of image carriers, a driving unit that rotationally drives the image carriers in an individual manner, and a phase adjusting unit that adjusts, based on a reference rotation position on one of the image carriers, phase of rotational fluctuation of the other image carrier per one rotation.