Image Density Fluctuation Correction in Photoconductor Drums
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Solution Overview
Problem
Image density fluctuations occur in image forming apparatuses due to tolerances in the photoconductive layer and dimensional errors in components like the photoconductor drum, charging roll, and developing sleeve, leading to inconsistent image quality despite proper setting of operating parameters.
Innovation Solution
An improved image forming apparatus and method that includes a rotating body with a sensor to detect its home position, allowing for separate acquisition of image density data from odd and even rotations, calculation of image density fluctuations, and correction of image forming conditions to minimize these fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If operating parameters are set properly, then image density should be consistent, but image density fluctuation still occurs due to tolerances in photoconductive layer and dimensional errors in components
Solution Approach 1:
The system performs preliminary measurement of image density at multiple positions on the photoconductor drum surface before actual image formation. Based on these measurements, it calculates correction values and adjusts operating parameters in advance to compensate for manufacturing tolerances and dimensional errors in components like the charging roll and developing sleeve.
Solution Approach 2:
The system continuously monitors image density using detection means positioned at multiple locations on the photoconductor drum. It feeds back the detected density values to the control unit, which calculates correction values and adjusts operating parameters dynamically to maintain consistent image density despite manufacturing variations in the photoconductive layer and mechanical components.
2Device complexity
If standard detection method is used, then detection process is simple, but image density fluctuation in sub-scanning direction cannot be adequately corrected
Solution Approach 1:
The detection system divides the photoconductor drum surface into multiple measurement positions arranged in the sub-scanning direction. Image density is measured separately at each position, allowing the system to identify and correct local density variations caused by manufacturing tolerances in the photoconductive layer and dimensional errors in rotating components.
Solution Approach 2:
The system extends detection from a single point to multiple positions across the sub-scanning dimension of the photoconductor drum. By measuring image density at multiple locations simultaneously and analyzing variations in the sub-scanning direction, the system can generate position-specific correction values that address dimensional errors in rotating components like the developing sleeve and transfer roll.
Data Source
AI summary
An image forming apparatus includes a rotating body to form an image, a sensor to detect a home position of the rotating body, a processor to acquire image density data of the image formed by the rotating body in odd-numbered rotation and even-numbered rotation of the rotating body separately based on a rotation home position signal output by the sensor, extract an image density fluctuation caused by a rotation of the rotating body, and correct an image forming condition based on the image density fluctuation.