Light-Amount Detecting Device for Laser Source Stabilization
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Solution Overview
Problem
In image forming apparatuses, the detection of light beam intensity for light source control is hindered by returning light entering the light source, leading to unstable laser oscillation and noise, and constant operation causes heat-related deterioration of light-emitting portions, while requiring adjustable light source and optical system alignment.
Innovation Solution
A light-amount detecting device with a branching optical element, light-condensing element, and light-receiving element, where the light-receiving element's surface is inclined to direct reflected light away from the light source, and a controller adjusts light-emitting portions based on detected light-amount, with a structure allowing positional adjustment of the light source and optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor detects light-amount of light beam emitted from light source to control light source, then light-amount control is achieved, but returning light enters light source causing unstable laser oscillation and noise
Solution Approach 1:
The patent divides the optical path into separate detection and scanning paths. The branching optical element separates the light beam from the light source into two distinct paths: one for scanning the photoreceptor drum and another for detection by the sensor. This segmentation prevents the returning detection light from entering the light source, eliminating the instability and noise issues while maintaining accurate light-amount control.
Solution Approach 2:
The patent extracts the detection light path from the main scanning light path using a branching optical element. By taking out a portion of the light beam through total internal reflection at the branching optical element, the system creates a separate detection channel that does not interfere with the scanning function and prevents returning light from affecting the light source.
2Ease of operation
If light-emitting portions are lit constantly to maintain operation, then image formation readiness is ensured, but heat generation causes deterioration of light-emitting portions
Solution Approach 1:
The patent implements periodic action by controlling the light source to emit light beams only when image formation is required, rather than operating constantly. The controller activates the light source based on detection signals, allowing the system to maintain readiness while significantly reducing cumulative heat generation and extending the lifespan of the light-emitting portions.
3Manufacturing precision
If light beam intensity is adjusted for stable image quality, then image density uniformity is improved, but additional control mechanisms increase device complexity
Solution Approach 1:
The patent implements feedback control by using the sensor to detect the light-amount of the light beam emitted from the light source and feeding this information back to the controller. The controller then adjusts the driving current to the light source based on the detected light-amount, creating a closed-loop system that automatically maintains uniform image density without requiring complex manual adjustment mechanisms.
Solution Approach 2:
The system performs self-service by automatically detecting and correcting light-amount variations. The sensor continuously monitors the light beam intensity, and the controller automatically adjusts the light source output to compensate for variations, eliminating the need for external intervention or complex mechanical adjustment mechanisms while maintaining precise image density uniformity.
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
Stabilizes laser output, prevents noise, reduces heat-induced deterioration, and allows for high-density and high-speed image formation with adjustable light source alignment.
Implementation Method 1
a branching optical element which divides the light beam emitted from the light source into a first light beam traveling in a predetermined direction and a second light beam traveling in a direction different to the predetermined direction
Implementation Method 2
a light-condensing element which condenses the second light beam
Implementation Method 3
a light-receiving element having a light-receiving surface which receives the second light beam condensed by the light-condensing element
Implementation Method 4
a light source which emits a light beam... a VCSEL array, having a plurality of light-emitting points
Data Source
AI summary
A light-amount detecting device includes: a light source which emits a light beam; a branching optical element which divides the light beam emitted from the light source into a first light beam traveling in a predetermined direction and a second light beam traveling in a direction different to the predetermined direction; a light-condensing element which condenses the second light beam; a light-receiving element having a light-receiving surface which receives the second light beam condensed by the light-condensing element; and a detector which detects a light-amount of the second light beam received by the light-receiving element, and at least one of a direction of reflected light of the second light beam reflected from the light-receiving surface of the light-receiving element and spread of the reflected light of the second light beam reflected from the light-receiving surface of the light-receiving element is adjusted to control a light-amount of the reflected light of the second light beam returning to the light source.