Trailing Edge Detection Circuit for Multi-Color Image Registration
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Solution Overview
Problem
Existing multi-color image forming apparatuses face reduced detection accuracy of positioning color image patterns due to fluctuations in the mounting angle of optical sensors, leading to incomplete registration compensation.
Innovation Solution
A positioning color image pattern trailing edge detecting circuit is introduced, which detects trailing edges of positioning color image patterns by determining when the optical sensor's output signal reaches a threshold value, set as a predetermined ratio of the peak value, and uses a control circuit to compensate for registration without relying on gravity center calculation methods. The optical sensor is constructed with a light emitting and receiving portion, where the plane including their optical axes is perpendicular to the transfer belt's direction, improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical sensor's mounting angle fluctuates, then the detection accuracy of positioning color image patterns deteriorates, but the registration compensation remains incomplete
Solution Approach 1:
The patent changes the detection parameter from gravity center calculation to trailing edge detection. By detecting the trailing edge position where the optical sensor signal reaches a predetermined threshold, the system achieves angle-insensitive detection. This parameter change makes the measurement independent of mounting angle fluctuations, simultaneously improving both detection accuracy and registration reliability.
Solution Approach 2:
The patent replaces the gravity center calculation method with a threshold-based trailing edge detection method. This substitution eliminates the need for complex calculations that are sensitive to angle variations, using instead a simpler threshold comparison approach that inherently compensates for mounting angle fluctuations, thereby maintaining high detection accuracy and reliable registration.
2Ease of operation
If the gravity center calculation method is used, then the detection process is simplified, but the detection accuracy deteriorates under angle fluctuations
Solution Approach 1:
The patent changes the detection parameter from gravity center position to trailing edge position. The trailing edge is identified by the point where the optical sensor signal reaches a predetermined threshold, providing a clear, unambiguous detection point that is insensitive to mounting angle variations, thus maintaining both simplicity and accuracy.
3Device complexity
If a single-structure positioning color image pattern is used, then the device complexity is reduced, but the detection accuracy deteriorates
Solution Approach 1:
The patent changes the detection parameter to trailing edge position, which can be accurately identified even with simple single-structure positioning patterns. This approach maintains device simplicity while achieving high detection accuracy by focusing on the clear threshold-based trailing edge transition rather than requiring complex pattern structures.
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 solution ensures complete registration compensation even with fluctuating optical sensor angles, enhancing detection accuracy of positioning color image patterns to several micrometers, thereby maintaining image quality.
Implementation Method 1
the optical sensor is constructed by a light emitting portion for emitting light, and a light receiving portion adapted to receive reflected light of the emitted light from the positioning color image patterns
Data Source
AI summary
In a multi-color image forming apparatus including a plurality of color image forming units adapted to form a plurality of different color images, a transfer belt to which positioning color image patterns are transferred by the color image forming units, and an optical sensor adapted to detect the positioning color image patterns, a positioning color image pattern trailing edge detecting circuit is provided to detect trailing edges of the positioning color image patterns by determining that an output signal of the optical sensor has reached a threshold value. The threshold value is a predetermined ratio of a peak value of the output signal of the optical sensor. A control circuit is provided to compensate for registration of the color image forming units in accordance with the detected trailing edges of the positioning color image patterns.