Clock Phase Synchronization in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining accurate image writing start positions due to phase differences in reference clocks caused by varying transmission line lengths, leading to degraded image quality, especially in color image formation.
Innovation Solution
The apparatus employs a sensor to detect light beams and output a detection signal, which is converted into parallel data using a sub-clock, allowing for precise adjustment of data delivery timing across units to synchronize with a reference clock, ensuring accurate image writing start positions without complicating the circuit construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple clock generation circuits are provided to generate pixel clocks for each unit, then phase differences between units can be eliminated, but the circuit construction becomes complicated
Solution Approach 1:
The patent merges multiple clock generation functions into a single oscillator that generates one reference clock signal. This reference clock is then distributed to all units (detection unit, image processing unit, laser drive unit) through transmission lines, eliminating the need for multiple separate clock generation circuits while maintaining phase synchronization capability through adjustable delay means.
2Device complexity
If a single oscillator is used to generate a reference clock for all units, then circuit construction is simplified, but phase differences occur due to varying transmission line lengths
Solution Approach 1:
The patent introduces adjustable delay means in each unit that can dynamically adjust the delay time of the reference clock signal. This dynamic adjustment capability allows each unit to compensate for fixed transmission line length differences, enabling phase synchronization to be achieved and maintained despite the simplified single-oscillator architecture.
3Measurement precision
If transmission line lengths from oscillator to respective units are made equal, then phase differences are eliminated, but device layout becomes constrained and complex
Solution Approach 1:
Instead of constraining the physical layout to achieve equal transmission line lengths, the patent employs adjustable delay means that can electronically compensate for length differences. This dynamic delay adjustment provides flexibility in layout design while maintaining phase synchronization, avoiding the complexity of enforcing strict geometric constraints.
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 enables high-accuracy control of image writing start positions, even with phase differences between operation clocks for data input and output units, thereby improving image quality by aligning scanning lines and maintaining precise image formation.
Implementation Method 1
a sensor configured to detect any of the light beams deflected by the deflection scanning unit and output a detection signal
Data Source
AI summary
An image forming apparatus capable of forming a high-resolution image without complicating a circuit construction. A difference between a phase of an operation clock for a BD detection unit and a phase of an operation clock for an image processing unit is measured by a phase measurement unit of the image forming apparatus, and a timing of data delivery between the BD detection unit and the image processing unit is adjusted by a BD input timing adjuster based on a measurement result. A difference between the phase of the operation clock for the image processing unit and a phase of an operation clock for a laser drive unit is measured by the phase measurement unit, and a timing of data delivery between the image processing unit and the laser drive unit is adjusted by an image output timing adjuster based on a measurement result.