Fixing Device Sheet Feeding Timing Control
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Solution Overview
Problem
In electrophotographic printers, rapid temperature rises due to high power supply voltage can lead to insufficient heat accumulation in the fixing device, causing fixing defects when the sheet is fed too early, as the heat is drawn from the fixing device by the first sheet.
Innovation Solution
An image forming apparatus with a controller that adjusts the sheet feeding timing based on the temperature gradient of the fixing device, delaying the start of sheet feeding if the temperature gradient is steep to ensure sufficient heat accumulation, and starting feeding when the temperature reaches a second temperature after a predetermined time has elapsed from the start of heating, or when a longer elapsed time indicates sufficient heat accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sheet feeding timing is set earlier based on a steep temperature gradient, then the productivity is improved, but a fixing defect is caused due to insufficient heat accumulation
Solution Approach 1:
The system performs preliminary heating to accumulate sufficient heat in the fixing device before sheet feeding begins. The controller monitors the temperature and only starts sheet feeding after the fixing device reaches a predetermined temperature threshold, ensuring heat accumulation is complete before the first sheet is processed.
Solution Approach 2:
The system uses temperature detection feedback to dynamically adjust sheet feeding timing. A temperature detector continuously monitors the fixing device temperature, and the controller uses this feedback information to determine the appropriate moment to start sheet feeding, preventing both premature feeding and excessive waiting.
2Reliability
If the sheet feeding timing is delayed to ensure heat accumulation, then the fixing quality is improved, but the productivity deteriorates
Solution Approach 1:
The system dynamically adjusts sheet feeding timing based on actual temperature conditions rather than using a fixed delay. The controller continuously adapts the feeding start time according to the measured temperature gradient and accumulated heat, optimizing both quality and productivity for each heating cycle.
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 suppresses fixing defects by ensuring the fixing device has sufficient heat before sheet feeding, regardless of the temperature gradient, thereby maintaining print quality.
Implementation Method 1
a fixing device configured to heat a sheet
Implementation Method 2
a temperature detector provided to the fixing device
Data Source
AI summary
An image forming apparatus configured to, in a case where a temperature of a heating unit is lower than a first temperature when receiving a printing command, start feeding of a sheet based on an elapsed time which is time elapsed from a predetermined timing after start of heating of the heating unit until the temperature of the heating unit has reached a second temperature higher than a first temperature and lower than a fixing temperature, the feeding of the sheet being started based on a timing at which the temperature of the heating unit has reached the second temperature in a case where the elapsed time is equal to or longer than a first time, and the feeding of the sheet being started when or after the first time has elapsed from the predetermined timing in a case where the elapsed time is shorter than the first time.