Laser Diode Control for Electrophotographic Imaging
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Solution Overview
Problem
Existing optical beam control systems in electrophotographic devices face issues with laser diode deterioration and photosensitive member degradation due to sudden current flow and continuous light emission until detection by the optical beam detection sensor.
Innovation Solution
An optical beam control device with a light-emission unit, scanning unit, luminous energy detection unit, optical beam detection unit, and control unit that gradually increases luminous energy from activation to first detection and extinguishes the optical beam during an extinction period to prevent component deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laser diode emits light continuously until detected by the BD sensor, then reliable optical beam detection is achieved, but deterioration of the laser diode and photosensitive member occurs
Solution Approach 1:
The patent applies periodic action by controlling the laser diode to emit light in periodic pulses rather than continuously. The light emission is synchronized with the scanning cycle, emitting during light-emission periods and extinguishing during extinction periods, which reduces cumulative exposure and deterioration while maintaining detection reliability through periodic detection opportunities.
Solution Approach 2:
The patent implements preliminary action by providing a warm-up period before normal operation where the laser diode emits light to stabilize its characteristics. During this preliminary phase, the system establishes stable emission before entering the periodic operation mode, ensuring reliable detection from the start of normal operation.
2Speed
If large current flows into the laser diode immediately after activation, then rapid light emission is achieved, but laser diode destruction may occur
Solution Approach 1:
The patent applies preliminary action by implementing a warm-up period where the laser diode is activated gradually before normal operation. During this preliminary phase, the drive current is controlled to increase progressively, allowing the laser diode to stabilize its characteristics and reach safe operating conditions before full-power emission begins.
Solution Approach 2:
The patent implements dynamics by making the drive current variable rather than constant. The current is dynamically adjusted based on the operational phase: gradually increasing during the warm-up period, maintaining controlled levels during periodic operation, and adapting to maintain reliability while achieving rapid emission when needed.
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
The solution effectively suppresses deterioration of the laser diode and photosensitive member by controlling light-emission timing and luminous energy, ensuring reliable detection and reducing wear on components.
Implementation Method 1
an optical beam is emitted by an optical beam emission device such as a laser diode
Implementation Method 2
a luminous energy detection sensor to detect the luminous energy of the emitted light, such as a PIN-type photodiode
Data Source
AI summary
An optical beam control device that can suppress deterioration of a laser diode and a photosensitive member is disclosed. Control is performed in such a manner that the luminous energy of emitted light is increased gradually in an initial period from the activation of a laser diode until the first generation of a BD detection signal. The initial period includes an extinction period in which the laser beam is extinguished. Therefore, deterioration of the light-emitting portion of the laser diode and the photosensitive member can be suppressed.