Color Sensor Transfer Voltage Control via Red Filter Detection
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Solution Overview
Problem
Image forming apparatuses face challenges in accurately detecting the arrival of a blue test image at a reading position due to variations in sheet conditions and apparatus states, leading to difficulties in determining the appropriate transfer voltage for efficient toner image transfer.
Innovation Solution
The apparatus employs a color sensor with red, blue, and green color filters and a controller that forms test images using yellow, magenta, and cyan toners, allowing for the determination of transfer voltages based on reading results from the color sensor, particularly using red image data to accurately detect the leading end of blue patterns and adjust transfer voltages accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a blue test image is read using a blue color filter, then the dynamic range of the read signal is larger, but it becomes difficult to accurately detect when the blue test image arrives at the reading position
Solution Approach 1:
The patent uses a red color filter as an intermediary to detect the leading end position of blue test images. Instead of directly using the blue color filter output for position detection, the system uses the red color filter output as a mediator to generate a leading end detection signal, which then triggers the sampling of blue color filter data. This resolves the contradiction by using an indirect detection method that overcomes the limitations of direct blue signal analysis.
2Measurement precision
If multiple test images with different transfer voltages are formed, then the determination of appropriate transfer voltage becomes more accurate, but the time required for reading and processing increases
Solution Approach 1:
The patent forms multiple test images with different transfer voltages in advance on the same sheet, and uses a leading end detection mechanism to automatically identify and select the appropriate test image for analysis. The system performs preliminary formation of multiple test patterns, then quickly identifies the relevant one through leading end detection using red color filter data, reducing the time needed for subsequent processing while maintaining accurate transfer voltage determination.
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 approach enhances the accuracy of reading blue test images and adjusts transfer voltages effectively, improving the detection of leading ends and density adjustments, thereby ensuring efficient toner image transfer.
Implementation Method 1
a dynamic range of a blue read signal value is larger than dynamic ranges of read signal values of other color components
Data Source
AI summary
An image forming unit forms test images of a color of the same type as a first color using toner of a second color and toner of a third color, transfers first and second test images, fixes the test images on a sheet, controls a sensor to read the test images, determines sampling timings for the test images based on an output signal related to the first test image outputted from the sensor using a color filter of a fourth color, acquires a result of reading the test images based on a reading result of the test images on the sheet by the color sensor using a color filter of the first color and the sampling timing, and determines a transfer voltage based on the result of reading the test images.