Laser Light Emission Control for Temperature-Induced Volume Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrophotographic image forming apparatuses, temperature variations cause light emission degradation in semiconductor lasers, leading to inconsistent light volumes across multiple light emitting elements due to individual differences in drive unit configurations, resulting in variations in light beams used for image formation.
Innovation Solution
A light emission apparatus with a detection element and a control unit that adjusts drive currents for each light emitting element based on the detected operating state, using a photo diode to monitor light amounts and derive threshold currents to maintain consistent light emission, and a correction current to reduce light emission delay, thereby stabilizing light output across different temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each drive unit individually controls light emitting elements based on common setting values, then temperature-induced light amount variation is corrected, but differences in circuit configurations cause inconsistent light volumes between multiple light emitting elements
Solution Approach 1:
The patent introduces individual threshold current values for each light emitting element as a corrective parameter. By detecting the actual threshold current of each element and using it to adjust drive currents, the system compensates for both temperature variations and individual element differences, achieving uniform light output across all elements
Solution Approach 2:
The patent implements a feedback mechanism where the light amount detected by the light receiving element is used to adjust the drive current. The system detects the actual light output, compares it with the target value, and modifies subsequent drive currents to maintain consistency, creating a closed-loop control system
2Speed
If drive current is increased to compensate for light emission delay, then light output response improves, but light amount consistency across temperature variations deteriorates
Solution Approach 1:
The patent dynamically adjusts drive currents based on real-time temperature conditions and detected light amounts. Rather than using fixed compensation values, the system continuously adapts the drive current to match both the required response speed and the target light amount consistency, optimizing performance across varying 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 solution ensures consistent light volumes from multiple light emitting elements by dynamically adjusting drive currents and correction currents, minimizing light emission delay and maintaining stable image formation quality despite temperature variations.
Implementation Method 1
a detection element (a photo diode) included in the laser light source to detect light
Implementation Method 2
a rise in temperature of semiconductor laser causes light amount variation, i.e., reduction in amount of light emission
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A light emission apparatus includes a detection unit, a first drive unit, and a second drive unit. The detection unit detects the state of a detection element. The first drive unit controls the light amount of a light beam to be emitted by a first light emitting element based on the state of the detection element detected by the detection unit. The second drive unit controls the light amount of a light beam to be emitted by a second light emitting element based on the state of the detection element detected by the detection unit.