Rotary Polygon Mirror Reflection Surface Identification
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Solution Overview
Problem
Conventional techniques for identifying the reflection surface of a rotary polygon mirror in electrophotographic image forming apparatuses require frequent memory updates, leading to reduced memory lifespan due to environmental variations affecting the interval between light detection and drive signal output timings.
Innovation Solution
A method involving a laser scanning device with a rotary polygon mirror, a drive motor, and a light detecting portion, where the interval between detection and drive signal output timings is measured and a standard interval is set, excluding the shortest and longest intervals, to identify the reflection surface, reducing the need for frequent memory updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional techniques are used to identify the reflection surface by monitoring drive signal output in predetermined division periods, then the reflection surface can be identified even with timing shifts due to environmental variations, but frequent memory updates are required which reduces memory lifespan
Solution Approach 1:
The system performs preliminary measurement of the interval between light detection timing and drive signal output timing during an identification period before normal operation. This preliminary action establishes a reference value that is stored in memory and used during normal operation, eliminating the need for frequent memory updates while maintaining identification accuracy under environmental variations
Solution Approach 2:
The system uses the existing light detection timing and drive signal output timing that are already generated for normal operation to perform the identification function. By measuring intervals between these existing signals, the system achieves self-service identification without requiring additional dedicated identification signals or frequent memory access
2Measurement precision
If the interval between light detection timing and drive signal output timing is frequently monitored and updated in memory, then accurate reflection surface identification is maintained under environmental variations, but the frequency of memory updates increases
Solution Approach 1:
The system performs preliminary measurement of the interval between light detection timing and drive signal output timing during an identification period before normal operation. This preliminary action establishes a reference value that is stored in memory and used during normal operation, eliminating the need for frequent memory updates while maintaining identification accuracy under environmental variations
Solution Approach 2:
The system performs identification measurements during a dedicated identification period rather than continuously during normal operation. This periodic action concentrates the measurement activity in specific intervals, reducing the overall frequency of memory updates while still capturing timing characteristics under various operating conditions
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 allows for accurate reflection surface identification while minimizing memory updates, thus extending the memory lifespan and accommodating environmental-induced timing shifts.
Implementation Method 1
a rotary polygon mirror having a plurality of reflection surfaces that reflect light emitted from the light source and configured to rotate such that the light is scanned by the plurality of reflection surfaces in sequence
Implementation Method 2
The light detecting portion detects the light scanned by the rotary polygon mirror, at a predetermined detection position inside a scanning area
Data Source
AI summary
A laser scanning device includes a rotary polygon mirror, a drive motor, a light detecting portion, a measurement processing portion, and an identification processing portion. The rotary polygon mirror has reflection surfaces and rotates such that light is scanned by the reflection surfaces in sequence. The light detecting portion detects the light scanned by the rotary polygon mirror. The measurement processing portion, in each of light detection cycles, measures an interval between a light detection timing and an output timing at which a drive signal that is to be input to a drive motor first after the detection timing, is output. The identification processing portion identifies a reflection surface corresponding to a standard interval, based on the standard interval and the measured interval, the standard interval being one of intervals acquired in the detection cycles that correspond to the reflection surfaces.