Polygon Mirror Mark Detection for Accurate Laser Scanning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face issues with fluctuating reflection surface lengths in polygon mirrors, leading to incorrect identification of scanning periods and errors in detecting marks due to operational conditions and external contaminants, affecting the accuracy of light beam scanning.
Innovation Solution
The apparatus incorporates a mark detector and an actuator to move the detector to a position corresponding to the operation condition of the exposure device, using a controller to adjust the detection timing of marks on the polygon mirror, and employs a nonvolatile storage device for individual control of exposure devices to compensate for changes in operational characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a reflective-type optical sensor is used to detect a mark on the motor axis, then the detection of reflection surfaces can be automated, but wrong reflection surfaces are detected due to waveform variations caused by operational conditions and overlapping detection timings
Solution Approach 1:
The patent applies the dynamics principle by making the optical sensor movable along the rotation direction of the polygon mirror. The sensor position is dynamically adjusted based on detected waveform characteristics - when mark detection accuracy deteriorates due to waveform variations from operational conditions, the sensor moves to optimize detection timing and prevent overlapping with light beam detection signals, thereby maintaining high measurement precision while preserving automated operation
Solution Approach 2:
The patent implements feedback by continuously monitoring the waveform of the sensor signal and using this information to control the position of the optical sensor. The detection timing of the mark is adjusted based on waveform analysis, and when accuracy deterioration is detected, the sensor position is automatically corrected. This closed-loop feedback mechanism ensures accurate reflection surface identification despite variations in operational conditions
2Device complexity
If the mark detector position is fixed, then the device structure is simplified, but detection accuracy deteriorates under varying operational conditions and rotation speeds
Solution Approach 1:
The patent transforms the fixed detector position into a dynamic, adjustable position. The optical sensor can move along the rotation direction of the polygon mirror, allowing the detection timing to be optimized for different operational conditions and rotation speeds. This dynamic positioning capability maintains high detection accuracy across varying operating parameters without significantly complicating the overall device structure
Solution Approach 2:
The patent changes the positional parameter of the optical sensor based on operational conditions. By adjusting the sensor position along the rotation direction according to detected waveform characteristics and operational parameters, the system adapts to varying rotation speeds and conditions, maintaining optimal detection accuracy without requiring a completely complex reconfiguration mechanism
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 ensures accurate identification of reflection surfaces, reducing errors in scanning and enhancing the precision of image formation by compensating for operational and environmental variations.
Implementation Method 1
a mark detector that detects a mark attached to a motor axis of the polygon motor
Data Source
AI summary
An image forming apparatus includes a photoconductor drum, an exposure device, a development device, and a controller. The exposure device irradiates the photoconductor drum with a light beam and thereby forms an electrostatic latent image. The development device causes toner to adhere to the electrostatic latent image and thereby generates a toner image. The controller controls the exposure device. Further the exposure device includes a polygon mirror, a polygon motor, a mark detector, and an actuator. The polygon mirror is configured to scan the light beam. The polygon motor is configured to rotate the polygon mirror. The mark detector is configured to detect a mark attached to a motor axis of the polygon motor. The actuator is configured to be enabled to move the mark detector. Furthermore, the controller moves the mark detector to a position corresponding to an operation condition of the exposure device using the actuator.