Laser Scanning Device Reflection Surface Identification
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Solution Overview
Problem
The accuracy of identifying a reflection surface of a rotary polygon mirror in a laser scanning device decreases when the rotation speed of the drive motor changes, as the interval between light detection timing and drive signal output timing does not consistently change with the speed change, affecting the precision of image formation in electrophotographic image forming apparatuses.
Innovation Solution
A laser scanning device with a rotary polygon mirror and a drive motor having magnetic poles of a number prime to the reflection surfaces, where the rotation speed is set to one of several specific speeds, and intervals between detection and output timings are measured and matched to reference intervals set for each speed, allowing accurate identification of the reflection surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotation speed of the drive motor is changed, then the productivity of the image forming apparatus is improved, but the measurement precision of the reflection surface identification decreases
Solution Approach 1:
The patent applies parameter changes by storing multiple reference intervals corresponding to different rotation speeds of the drive motor. When the rotation speed changes, the system selects the appropriate reference interval from storage based on the current speed, thereby maintaining accurate reflection surface identification across varying productivity levels. This resolves the contradiction by adapting the measurement parameters to match the operational conditions.
Solution Approach 2:
The system dynamically adjusts the reference interval selection based on the actual rotation speed of the drive motor. By continuously monitoring the rotation speed and selecting the corresponding reference interval in real-time, the system maintains measurement precision across different operational speeds, thus resolving the contradiction between productivity improvement through speed variation and maintaining identification accuracy.
2Device complexity
If a single reference interval is used for reflection surface identification, then the device complexity is reduced, but the adaptability to different rotation speeds decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple reference intervals corresponding to different rotation speeds before actual operation. This preparation work is done in advance, so when the drive motor operates at different speeds, the system can immediately select the appropriate reference interval without complex real-time calculations, thus maintaining low device complexity while achieving high adaptability.
Solution Approach 2:
The system achieves universality by creating a reference interval storage that serves multiple rotation speed conditions. A single storage structure contains reference intervals for various speeds, making the identification system adaptable to different operational conditions without requiring separate identification mechanisms for each speed, thereby maintaining simplicity while enhancing versatility.
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 prevents a decrease in accuracy when the drive motor's rotation speed changes, ensuring precise identification and correction of reflection surfaces, thereby maintaining image formation quality.
Implementation Method 1
a rotary polygon mirror, and an image forming apparatus including a laser scanning device... the rotary polygon mirror has a plurality of reflection surfaces that reflect light emitted from the light source
Data Source
AI summary
An image forming apparatus includes: a speed setting portion configured to set a rotation speed of a drive motor to one of a plurality of predetermined specific speeds; a measurement processing portion configured to, in each of a plurality of detection cycles in which light is detected after scanning by a polygon mirror, measure an interval between a detection timing of the light and an output timing at which a drive signal input to the drive motor of the polygon mirror first after the detection timing, is output; and an identification processing portion configured to identify a reference reflection surface that corresponds to a reference interval, based on the measured interval and the reference interval corresponding to a specific speed at a time when the measured interval was measured, the reference interval being among reference intervals that have been set in advance for each of the specific speeds.