Image Forming Apparatus Temperature Detection for Color Misregistration
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately correcting color misregistration due to temperature rise issues, as internal air flows affect temperature sensors, leading to incomplete temperature detection and incorrect correction values, especially when the rotary polygon mirror is rotated without light source emission.
Innovation Solution
An image forming apparatus with a temperature detector on the drive circuit board outside the housing, which detects the temperature rise accurately and corrects color misregistration by switching rotation control from FG to BD method based on detected temperature and pattern sensor results, ensuring precise alignment of toner images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the temperature sensor is disposed at the center of the housing to remove the adverse effect of internal air flows, then the temperature sensor is protected from air flow interference, but the temperature rise amount detected is lower than the actual temperature rise amount adjacent to the deflector, causing inaccurate color misregistration correction
Solution Approach 1:
The patent introduces a thermal conduction member as an intermediary between the deflector (heat source) and the temperature sensor. This mediator transfers the temperature rise from the deflector to the sensor located in the housing center, allowing accurate temperature detection without direct exposure to air flows. The thermal conduction member conducts heat from the deflector to the sensor, bridging the gap between the heat source and the protected sensor location.
2Stability of the object's composition
If the rotary polygon mirror is rotated without turning on the light source to achieve stationary rotation in early stage, then the rotation stability is improved, but the temperature rise amount of the drive circuit board becomes smaller than the internal housing temperature rise, causing incorrect correction values
Solution Approach 1:
The patent applies preliminary action by heating the drive circuit board with a heater before the rotary polygon mirror rotation begins. This ensures that the temperature sensor on the drive circuit board detects the full temperature rise that will occur during operation, even when the light source is not yet on. The heater pre-heats the circuit board to match the thermal conditions that will exist during actual scanning operations, allowing accurate temperature-based correction values to be generated from the start.
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 effectively corrects color misregistration by accurately measuring temperature rise and adjusting rotation control, improving image alignment and reducing downtime, thus enhancing the overall efficiency and accuracy of the image forming process.
Implementation Method 1
a temperature detector, disposed on the drive circuit board provided outside of the housing, configured to detect a temperature of the drive circuit board
Implementation Method 2
a rotary polygon mirror configured to deflect the light beams emitted from the light source so that the light beams scan on the surfaces of the plurality of photosensitive members
Implementation Method 3
a pattern detector configured to detect a registration correction pattern included in the toner images transferred onto the intermediate transfer member
Data Source
AI summary
An image forming apparatus including a controller, which starts rotation of a rotary polygon mirror when a predetermined condition is satisfied, rotates the rotary polygon mirror at a predetermined rotation speed based on a first pulse in a first state in which light beams are not emitted from a light source, thereafter starts emission of the light beams, switches a rotation control based on the first pulse to a rotation control based on the second pulse, and rotates the rotary polygon mirror at the predetermined rotation speed based on the second pulse in a second state in which the light beams are emitted from the light source, and thereafter detects a temperature of a drive circuit board by a temperature detector, and corrects color misregistration using a detected temperature of the temperature detector and the detection result of a pattern detector.