Optical Scanning Device Dust and Thermal Compensation
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Solution Overview
Problem
Conventional optical scanning devices face issues with dust accumulation on the rotatable polygon mirror, leading to uneven image density and shifting scanning positions due to heat-induced deformation, which affect image quality over time and are not easily detectable during operation.
Innovation Solution
An optical scanning device equipped with a light source, a rotatable polygon mirror, an optical member, an output unit, and a light quantity sensor, where the sensor detects changes in light quantity and reflectivity, allowing for real-time control of the light source to maintain image quality by correcting for dust accumulation and heat-induced shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotatable polygon mirror is rotated at high speed, then productivity is improved, but dust adheres to the reflecting surface causing image density unevenness
Solution Approach 1:
The light quantity sensor detects dust accumulation on the reflecting surface before it significantly degrades image quality. By performing detection in advance during operation, the system can trigger maintenance actions or compensate for the degradation, preventing the dust accumulation from reaching a critical level that would cause noticeable image density unevenness
Solution Approach 2:
The light quantity sensor provides continuous feedback about the light quantity of the luminous flux reflected by the rotatable polygon mirror. This feedback loop allows the system to monitor dust accumulation in real-time and respond appropriately, either by alerting operators for maintenance or by adjusting operational parameters to compensate for the degradation
2Productivity
If the rotatable polygon mirror is rotated at high speed, then productivity is improved, but heat causes optical box deformation and scanning position shift
Solution Approach 1:
The light quantity sensor detects changes in light quantity that indicate optical box deformation before it causes significant scanning position errors. By monitoring the light quantity during operation, the system can detect the onset of thermal deformation and trigger compensatory measures or maintenance actions before the scanning position accuracy is significantly compromised
Solution Approach 2:
Continuous monitoring of light quantity provides feedback about thermal effects on the optical box. This feedback enables the system to detect scanning position shifts caused by heat-induced deformation and respond by adjusting operational parameters or alerting operators to cool the system before precision is lost
3Device complexity
If conventional technology is used, then device complexity is low, but changes in reflectivity and scanning position cannot be detected during operation
Solution Approach 1:
The light quantity sensor serves multiple functions: it monitors dust accumulation on the reflecting surface, detects thermal deformation of the optical box, and provides data for predicting maintenance needs. By using a single sensor to perform multiple monitoring tasks, the system achieves comprehensive performance monitoring without proportionally increasing complexity
Solution Approach 2:
The system uses the existing optical path and components to enable self-diagnosis. The light quantity sensor utilizes the luminous flux already present in the system to monitor the health of the rotatable polygon mirror and optical box, allowing the system to self-assess its performance without requiring separate complex diagnostic equipment
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
Enables detection and correction of reflectivity decreases and scanning position misalignments in real-time, preventing image degradation and ensuring high-quality image output over time.
Implementation Method 1
a rotatable polygon mirror configured to deflect the luminous flux emitted from the light source and scan in a main scanning direction
Implementation Method 2
a detecting unit provided on the upstream side of the output unit in the main scanning direction and configured to detect a light quantity of the luminous flux
Implementation Method 3
heat generated by coils and electric circuits that rotate the rotatable polygon mirror causes the optical box to expand and deform due to the heat
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
An optical scanning device includes a light source, a rotatable polygon mirror, an optical member, an output portion and a detector. The optical member guides the luminous flux scanned by the rotatable polygon mirror to an image bearing member. The output portion is provided on an upstream side of the optical member in the scanning direction and outputs a signal corresponding to receiving the luminous flux. The detector is provided on the upstream side of the output portion and detects a light quantity of the luminous flux. A controller controls the light source based on the signal outputted from the output portion and the light quantity detected by the detector. The luminous flux reaching the detector is reflected at a position closer to an end portion of a reflecting surface of the rotatable polygon mirror in the main scanning direction than the luminous flux reaching the output portion.