Infrared Sensor Preheating for Fixing Unit Detection Accuracy
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in accurately detecting recording sheets, especially in low-temperature conditions, due to the sensitivity of infrared sensors being affected by the temperature state and the type of images being fixed, leading to potential false detections.
Innovation Solution
Incorporating a heating unit that heats the infrared sensor using the heat emitted by the heating roller of the fixing device, ensuring the sensor operates effectively across varying temperature conditions and image types by maintaining optimal detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an infrared sensor is used to detect recording sheets in low-temperature conditions, then detection capability is maintained, but detection accuracy deteriorates due to reduced sensor sensitivity
Solution Approach 1:
The patent applies preliminary action by heating the infrared sensor before it performs detection in low-temperature conditions. The heating unit pre-warms the sensor to a predetermined temperature, ensuring the sensor maintains optimal sensitivity and detection accuracy when detecting recording sheets that pass through the fixing unit at low temperatures.
2Measurement precision
If the infrared sensor is heated to maintain detection sensitivity, then detection accuracy improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by controlling the heating unit to operate only when needed - specifically when the fixing unit is in a low-temperature state and detection is required. The heating is applied periodically or on-demand rather than continuously, warming the infrared sensor only during periods when low-temperature detection challenges exist, thereby reducing overall energy consumption while maintaining detection accuracy when required.
3Ease of operation
If the infrared sensor detects thermal energy from recording sheets, then non-contact detection is achieved, but false detections occur due to varying thermal signatures of different image types
Solution Approach 1:
The patent applies parameter changes by adjusting the operating temperature parameter of the infrared sensor through the heating unit. By maintaining the sensor at a predetermined optimal temperature, the sensor's detection characteristics are standardized, which helps distinguish genuine thermal signatures of recording sheets from varying thermal patterns of different image types, thereby reducing false detections while maintaining non-contact detection capability.
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
Ensures consistent and accurate detection of recording sheets regardless of temperature states and image types, improving the reliability of the fixing process by preheating the infrared sensor with air blown by an exhaust fan, enhancing detection sensitivity and preventing false detections.
Implementation Method 1
a detector that is disposed at a position downstream from the fixing unit in a direction in which the recording medium is transported and that detects the recording medium by detecting thermal energy emitted by the recording medium
Implementation Method 2
a heating unit that heats the detector
Data Source
AI summary
A fixing device includes a fixing unit that heats and fixes an unfixed image held on a recording medium onto the recording medium, a detector that is disposed at a position downstream from the fixing unit in a direction in which the recording medium is transported and that detects the recording medium by detecting thermal energy emitted by the recording medium, and a heating unit that heats the detector.