Optical Writing Synchronization Gain Switching for Image Forming
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face issues with erroneous detection of writing start timing due to stray light or insufficient light, leading to synchronization detection failures.
Innovation Solution
The apparatus includes a synchronization detector irradiated with multiple laser beams of different colors, a gain switch circuit, and a gain-control-signal selection circuit to maintain consistent light levels and adjust gain based on light-emission control signals, ensuring accurate detection of writing start timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain of the synchronization detector is fixed, then the device complexity is reduced, but detection precision deteriorates when light amount fluctuates
Solution Approach 1:
The synchronization detector employs a variable gain amplifier that can dynamically adjust its gain value based on the detected light amount. When the light amount is sufficient, the gain is set to a lower value to prevent saturation from stray light. When the light amount is insufficient, the gain is increased to amplify the weak synchronization signal. This dynamic adaptation resolves the contradiction by allowing the detector to maintain high precision across varying light conditions without requiring multiple fixed-gain detectors.
Solution Approach 2:
The invention changes the electrical parameter (gain) of the synchronization detector based on the optical parameter (light amount). A light amount detection circuit monitors the intensity of the laser beam, and based on this measurement, the gain value is adjusted accordingly. This parameter coupling allows the system to adapt to different printing conditions (such as different paper types or ambient light levels) while maintaining reliable synchronization detection.
2Reliability
If a single gain value is used for the synchronization detector, then the ease of operation is improved, but reliability deteriorates due to erroneous detection or detection omission
Solution Approach 1:
The synchronization detector system performs self-adjustment through an automatic gain control mechanism. The light amount detection circuit continuously monitors the incoming light, and the variable gain amplifier automatically adjusts its gain value without requiring manual intervention. This self-service capability ensures reliable detection across varying conditions while maintaining ease of operation, as the system adapts automatically without user involvement.
Solution Approach 2:
The system implements a feedback loop where the detected light amount is fed back to control the gain setting of the synchronization detector. The light amount detection circuit measures the intensity of the laser beam, and this information is used to adjust the gain value in real-time. This feedback mechanism ensures that the detector operates at optimal sensitivity for the current light conditions, preventing both erroneous detection (when gain is too high) and detection omission (when gain is too low).
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 configuration reliably detects synchronization without errors, even with varying light conditions, enhancing the precision of image formation.
Implementation Method 1
The reflector deflects the first light and the second light
Implementation Method 2
The synchronization detector detects the first light and the second light to detect the writing start timing
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
An image forming apparatus includes a photoconductor (106) to form an electrostatic latent image, an optical writing device (1), a first light emitter (LD), a second light emitter (LD), a reflector (103), a synchronization detector (104), and circuitry (102, 104a, 202). The optical writing device includes a first light emitter to irradiate a first light and a second light emitter to irradiate a second light. The reflector deflects the first light and the second light. The synchronization detector detects the first light and the second light to detect a writing start timing. The circuitry outputs a light-emission control signal to control light emission state, outputs multiple gain signals corresponding to the first light emitter and the second light emitter, selects one gain signal from the multiple gain signals as a gain selection signal, and switches a gain of the synchronization detector based on the one gain signal.