Intermediate Transfer Belt Speed Control via Mark Detection
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining precise speed control of belts due to micro-vibrations and elasticity, leading to irregularities in toner image transfer, especially when joints in the scale on the intermediate transfer belt cause inaccurate speed detection.
Innovation Solution
An image forming apparatus with a rotating body featuring marks at intervals, a sensor for detecting these marks, an actual interval measuring unit, a selecting unit that chooses the mean value of past intervals within a normal range for feedback control, and a control unit to maintain target interval alignment, ensuring stable belt rotation and image transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scale with joints is provided on the intermediate transfer belt to detect speed, then the speed detection mechanism is established, but the joints cause gaps in mark detection leading to inaccurate speed measurement
Solution Approach 1:
The patent extracts the problematic joints from the scale structure by using overlapping scales that eliminate joint gaps. The overlapping configuration ensures continuous mark detection without interruptions, removing the source of measurement errors while maintaining the speed detection function.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing the relationship between scale position and belt speed in a lookup table. This allows the system to compensate for any remaining detection variations and maintain accurate speed measurement throughout the belt's rotation cycle.
2Stability of the object's composition
If feedback control is used to maintain constant belt speed, then speed stability is improved, but micro-vibrations and elasticity cause detection inaccuracies that undermine control precision
Solution Approach 1:
The patent implements feedback control by continuously comparing the detected belt speed with the target speed and adjusting the motor drive accordingly. The feedback loop uses the averaged speed data from multiple marks to maintain stable belt speed despite micro-vibrations and elastic deformations.
Solution Approach 2:
The patent prepares compensation data in advance by creating a lookup table that maps scale positions to corrected speed values. This preliminary action allows the system to pre-compensate for systematic errors before they affect the feedback control accuracy.
3Device complexity
If the rotational speed of the roller is used to calculate belt speed, then the speed calculation is simplified, but the elastic nature of the belt causes speed deviations that reduce control accuracy
Solution Approach 1:
The patent replaces the mechanical calculation method (using roller rotational speed) with an optical detection method. Marks are attached to the belt and detected by a sensor, directly measuring belt speed without relying on roller rotation assumptions. This substitution eliminates errors caused by belt elasticity and micro-vibrations.
Solution Approach 2:
The patent changes the measurement parameter from indirect roller rotational speed to direct mark passage timing. By measuring the time interval between successive mark detections, the system obtains accurate belt speed information that reflects actual belt motion rather than inferred roller motion.
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 stabilizes the rotation of the belts, preventing irregularities in toner image transfer and ensuring high-quality image formation by accurately controlling the speed of the intermediate transfer belt, even when joints or toner adheres to the marks.
Implementation Method 1
a sensor that outputs pulses whenever each mark is detected
Data Source
AI summary
If a velocity calculated by a velocity calculating unit deviates from a normal range, a target velocity is used as a feedback amount, an actuation amount corresponding to a deviation Ve=0 between the feedback amount Vf=Vt and the target velocity Vt is calculated, and a driving power corresponding to this actuation amount is supplied to a motor. A conveyor belt can be driven stably without causing irregularity in a speed of the conveyor belt.