Color Image Forming Apparatus Write Start Timing Correction
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Solution Overview
Problem
In electrophotographic image forming apparatuses, changes in light beam intensity due to varying image forming conditions cause positional shifts in scanning, leading to color tone changes and degraded image quality, especially in color machines where precise timing is critical.
Innovation Solution
An electrophotographic color image forming apparatus incorporates a multifaceted reflector for light deflection, a synchronization detection element, and processing circuitry to adjust the write start timing and correct color shifts by calculating detection shift correction values based on light amounts, ensuring accurate light emission control and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light amount of the beam is changed according to image forming conditions, then the image forming conditions can be adapted, but the detection waveform of the synchronization detection sensor changes causing positional shift
Solution Approach 1:
The patent uses the synchronization detection sensor to detect changes in the detection waveform caused by light amount variations, and the processing circuitry calculates correction values based on these detected changes to adjust the write start timing, forming a closed-loop feedback system that maintains precision despite adaptability
Solution Approach 2:
The patent changes the parameter of write start timing based on the detected light amount conditions, adjusting the timing parameter dynamically to compensate for waveform changes and maintain accurate positioning while adapting to different image forming conditions
2Manufacturing precision
If the write start timing is adjusted to correct color shifts, then color accuracy is improved, but additional processing complexity is introduced
Solution Approach 1:
The patent performs preliminary detection of the detection waveform characteristics and pre-calculates correction values before actual image formation, storing these correction values for later application, which simplifies the real-time processing complexity while maintaining color accuracy
Solution Approach 2:
The patent introduces an intermediary processing step where the processing circuitry calculates correction values based on detected waveform changes, acting as a mediator between the synchronization detection sensor and the write start timing control to achieve color accuracy without excessive complexity
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 effectively stabilizes the write start timing and corrects color shifts, maintaining high image quality across varying light conditions, thereby preventing positional shifts and ensuring consistent color output.
Implementation Method 1
a light-emitting element to irradiate the photoconductor with light
Implementation Method 2
a synchronization detection element to detect a write start timing of the electrostatic latent image with the light with which the photoconductor is irradiated
Data Source
AI summary
An electrophotographic color image forming apparatus develops an electrostatic latent image with a developer to form an image and includes a photoconductor and an optical writing device. The writing device includes a light-emitting element, a light emission control element, a deflector element, a synchronization detection element, a memory, and processing circuitry. The memory stores a first light amount of the light-emitting element when a color shift is corrected. The processing circuitry corrects the color shift by adjusting a write start timing, and corrects a detection shift generated when a light amount of light incident on the synchronization detection element fluctuates. The processing circuitry calculates a detection shift correction value of the detection shift of the synchronization detection element, using the first light amount and a second light amount determined as a lighting condition of the light-emitting element, and adds the detection shift correction value to a color shift correction value.