Spread Clock Signal Correction for Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses, frequency distortion in the clock signal output by the Spread Spectrum Clock Generator (SSCG) affects the accuracy of detecting intervals between patch images, leading to reduced precision in resist correction processing, especially in tandem-type color image forming systems.
Innovation Solution
An image forming apparatus with a spread clock signal output section that spreads a clock signal at a predetermined standard frequency, a patch toner image intervals calculating section to determine intervals based on the clock signals, and a calculation result correcting section to adjust for frequency errors, ensuring accurate interval correction and reduced radiation noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a spread clock signal is used to reduce radiation noise, then radiation noise is reduced, but frequency distortion occurs in the clock signal
Solution Approach 1:
The patent implements a feedback mechanism where the actual frequency of the spread clock signal is measured and compared with the standard frequency. Based on this comparison, a correction value is calculated and applied to adjust the clock signal frequency, thereby eliminating the frequency distortion caused by spreading while maintaining the radiation noise reduction benefit
Solution Approach 2:
The patent dynamically adjusts the frequency parameter of the spread clock signal by adding a correction value derived from frequency measurement. This parameter change compensates for the frequency distortion introduced by the spreading process, ensuring accurate frequency control despite the presence of spread spectrum modulation
2Object-affected harmful factors
If the clock signal frequency is spread to lower peak value, then radiation noise is reduced, but detection accuracy of patch image intervals deteriorates
Solution Approach 1:
The system measures the actual frequency of the spread clock signal and uses this feedback information to calculate a correction value. This correction value is then applied to adjust timing measurements of patch image intervals, compensating for frequency variations and maintaining measurement accuracy despite frequency spreading
Solution Approach 2:
The patent replaces direct mechanical/time-based measurement with a corrected calculation approach. Instead of relying solely on the spread clock signal for timing, the system calculates interval corrections based on measured frequency deviations, substituting pure time-counting with a compensated measurement method
Data Source
AI summary
An image forming apparatus includes plural image forming sections for forming toner images of different colors. A patch toner image forming section forms patch toner images side-by-side onto a moving transfer body by using the image forming sections. A spread clock signal output section spreads a clock signal having a predetermined standard frequency at a predetermined spreading ratio and outputs the clock signal. A patch toner image intervals calculating section calculates intervals between the patch toner images on the transfer body based on the number of clock signals outputted from the spread clock signal output section and the standard frequency. A calculation result correcting section counts spread clock signals outputted during a time interval from the spread clock signal output section, and corrects a calculation result given by the patch toner image intervals calculating section based on the result of the counting.