Laser Power Compensation for Scanning Rate Variations
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Solution Overview
Problem
Scanning rate variations in electrophotographic devices, such as laser printers and copier machines, lead to inconsistencies in image darkness levels due to factors like temperature and humidity, affecting the efficiency and quality of printed images.
Innovation Solution
A method is implemented to measure the actual scanning rate and adjust the laser light source intensity using a compensation factor, calculated based on the difference between the basal and actual scanning rates, to maintain a predetermined image darkness level, thereby ensuring consistent print quality across devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a torsion oscillator or resonant galvanometer structure is used to increase scanning efficiency, then device productivity is improved, but scanning rate variations occur due to ambient conditions, deteriorating image darkness consistency
Solution Approach 1:
The system continuously monitors the actual scanning rate and compares it to the expected scanning rate. Based on the deviation, the controller dynamically adjusts the laser intensity to compensate for scanning rate variations, ensuring consistent image darkness. This closed-loop feedback mechanism resolves the contradiction by maintaining image quality while preserving the high scanning efficiency of resonant galvanometer structures.
Solution Approach 2:
The invention changes the laser intensity parameter dynamically based on the measured scanning rate deviations. By adjusting the laser intensity parameter in response to ambient condition-induced scanning rate variations, the system maintains consistent image darkness while retaining the productivity benefits of resonant scanning.
2Productivity
If scanning rate is increased to improve process speed, then device productivity is improved, but image darkness level becomes inconsistent compared to slower scanning rates
Solution Approach 1:
The system transitions from a static laser intensity setting to a dynamic adjustment mechanism. The laser intensity is continuously adapted based on real-time scanning rate measurements, allowing the system to maintain optimal image darkness across varying scanning rates without sacrificing process speed.
Solution Approach 2:
The invention dynamically changes the laser intensity parameter in response to scanning rate variations. By calculating compensation factors based on the relationship between scanning rate and image darkness, the system maintains consistent image quality across different process speeds.
3Adaptability or versatility
If ambient conditions vary (temperature, humidity, air pressure, altitude), then device adaptability is reduced, but scanning rate variations occur, affecting image quality
Solution Approach 1:
The system incorporates feedback mechanisms that continuously monitor scanning rate deviations caused by ambient conditions and automatically adjust laser intensity accordingly. This enables the device to adapt to varying environmental conditions while maintaining scanning rate stability and image quality consistency.
Solution Approach 2:
The device performs self-adjustment by automatically detecting scanning rate variations and compensating for them through laser intensity modulation. This self-service capability eliminates the need for manual calibration or external intervention when ambient conditions change.
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 effectively compensates for scanning rate variations, ensuring consistent image darkness and improved print quality by dynamically adjusting the laser intensity, thus addressing the issue of rate inconsistencies and maintaining desired image characteristics.
Implementation Method 1
an EP device uses a laser to scan multiple scan lines on a photoconductor to form a latent image
Implementation Method 2
torsion oscillator or resonant galvanometer structures can replace the traditional spinning polygon mirror to create scan lines
Implementation Method 3
differences in ambient conditions such as temperature, humidity, air pressure, altitude, etc. may affect the oscillation rate of the torsion oscillator or resonant galvanometer structure
Data Source
AI summary
Methods are provided for an EP device such as a laser printer or copier, to compensate for variations in scanning rate. At intervals during a scanning process, actual scanning rate is measured and compared to a basal scanning rate of the EP device. Adjustments in the laser light source intensity are then implemented to preserve a predetermined image darkness notwithstanding variations in scanning rate, thereby preserving print quality. To implement the adjustments, a compensation factor is calculated based on a difference between the basal scanning rate of the device and the measured actual scanning rate. The steps of measuring an actual scanning rate, calculating a compensation factor, and adjusting laser operating intensity may be performed during a warming-up function at EP device at start-up, during a print job, or both. An EP device utilizing the method of the present invention is provided also.