Image Forming Apparatus Fixing Temperature Control
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Solution Overview
Problem
In image forming apparatuses, especially in humid environments, the environmental heater can cause temperature discrepancies, leading to inaccurate determination of the optimum fixing temperature for toner image fixation, as the environment sensor may detect higher temperatures than those near the fixing device, affecting the fixing performance.
Innovation Solution
An image forming apparatus with a first sensor for environmental temperature detection, a second sensor for fixing unit temperature detection, a sheet container heater, and a controller that adjusts power supply to the fixing heater based on both sensor readings and the state of a switch to minimize the influence of the environmental heater, ensuring accurate fixing temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an environmental heater is installed to prevent moisture absorption and dew condensation in humid areas, then the reliability of the image forming apparatus is improved, but the temperature detection accuracy of the environment sensor deteriorates due to heat generation causing false high temperature readings
Solution Approach 1:
The patent divides the heating function into two separate heating elements: an environmental heater for preventing moisture absorption and dew condensation, and a fixing heater for toner image fixation. This segmentation allows independent control of each heating function, enabling the environment sensor to accurately detect ambient temperature without interference from the fixing heater's thermal field, while the sheet container heater maintains its dehumidification function.
Solution Approach 2:
The patent introduces a sheet container heater as an intermediary heating element positioned between the environment sensor and the fixing heater. This intermediary heater (sheet container heater) is controlled based on environment sensor readings, allowing it to provide necessary thermal management for moisture prevention while the controller compensates for its thermal influence on the environment sensor, thereby maintaining accurate temperature detection.
2Measurement precision
If the environment sensor is arranged at a position away from the fixing device to avoid heat interference, then the measurement precision of environmental temperature is improved, but the difference between detected temperature and actual fixing device temperature increases, worsening the ability to determine optimum fixing temperature
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors both the environment sensor temperature and the fixing heater temperature, then calculates the temperature difference. Based on this feedback, the controller dynamically adjusts the fixing heater power supply to compensate for environmental variations, ensuring accurate fixing temperature control regardless of the environment sensor's position relative to the fixing device.
Solution Approach 2:
The patent changes the control parameter from direct environment sensor temperature reading to a corrected temperature value that accounts for the sheet container heater's thermal influence. The controller adjusts the sheet container heater power supply based on the detected temperature and switch state, dynamically modifying the heating parameter to maintain accurate environmental temperature detection while adapting to different operational conditions.
3Reliability
If the sheet container heater is operated continuously to maintain optimal temperature in humid environments, then the reliability of moisture prevention is improved, but the energy consumption increases
Solution Approach 1:
The patent implements periodic or conditional operation of the sheet container heater rather than continuous operation. The controller activates the sheet container heater based on detected temperature, switch state, and humidity conditions, turning it on only when necessary to prevent moisture absorption and dew condensation. This periodic action maintains reliable moisture prevention while significantly reducing unnecessary energy consumption during periods when heating is not required.
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 allows for precise control of the fixing temperature, reducing the impact of environmental heater-induced temperature discrepancies and improving image quality by maintaining optimal fixing conditions.
Implementation Method 1
a fixing unit configured to fix the image on the sheet by heating the image on the sheet, the fixing unit having a fixing heater
Implementation Method 2
a sheet container heater configured to heat the sheet in the sheet container
Implementation Method 3
an environment sensor which detects environmental information such as temperature and humidity is provided. The environment sensor is provided in the image forming apparatus and includes an environment detection element such as a temperature detection element
Implementation Method 4
a second sensor configured to detect a temperature of the fixing unit
Implementation Method 5
a controller configured to control a power supply to the fixing heater based on a detection result of the first sensor, a detection result of the second sensor, and a state of the switch
Data Source
AI summary
An image forming apparatus includes a first sensor configured to detect a temperature; an image forming unit configured to form an image; a sheet container configured to contain sheets; a conveyance roller configured to convey a sheet from the sheet container; a transfer unit configured to transfer the image on the sheet conveyed by the conveyance roller; a fixing unit configured to fix the image on the sheet by heating the image on the sheet; a second sensor configured to detect a temperature of the fixing unit; a sheet container heater configured to heat the sheet in the sheet container, wherein the sheet container heater is provided at a position where a distance from the first sensor to the sheet container heater is closer than a distance from the fixing unit to the sheet container heater.