Fixing Device Temperature Control for Image Formers
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Solution Overview
Problem
In image forming apparatuses, the fixing device faces challenges in maintaining optimal temperature control, especially during prolonged idle periods or intervals between print jobs, as heat distribution between the sheet passing and non-sheet passing areas of the fixing belt is uneven, affecting printing quality.
Innovation Solution
A control system that adjusts the target temperature of the fixing device based on the interval between image formation processes, using sensors to monitor temperatures in both the sheet passing and non-sheet passing areas, and adjusts the heating units accordingly to maintain optimal temperatures and prevent overheating or underheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater temperature is controlled based only on the sheet passing area temperature, then the printing/fixing can be performed sufficiently during repeated image forming processes, but the non-sheet passing area temperature remains high causing potential overheating and sticking issues
Solution Approach 1:
The patent applies local quality by dividing the fixing belt into two distinct zones: a sheet passing area and a non-sheet passing area. Each zone is equipped with its own temperature sensor (first temperature sensor in the sheet passing area, second temperature sensor in the non-sheet passing area) and the heater is controlled independently for each zone. This allows the non-sheet passing area to be cooled separately from the sheet passing area, preventing overheating and sticking in the non-sheet passing region while maintaining adequate temperature for fixing in the sheet passing region.
2Use of energy by moving object
If the heater temperature is reduced during long idle periods, then energy consumption is reduced, but the fixing belt temperature drops below optimal fixing temperature
Solution Approach 1:
The patent implements dynamic temperature control by adjusting the heater temperature based on the operational state of the image forming apparatus. When the apparatus is in a repeated image forming process state, the heater is controlled to maintain optimal fixing temperature. When the apparatus enters a long idle period, the controller reduces the heater temperature to lower energy consumption. The system dynamically transitions between these states based on detected printing activity, ensuring energy efficiency during idle periods while maintaining adequate fixing capability when printing resumes.
3Temperature
If the heater temperature is increased to compensate for heat loss to surrounding components during idle periods, then optimal fixing temperature is maintained, but energy consumption increases
Solution Approach 1:
The patent segments the heating control into distinct operational modes: a first heating control mode during repeated image forming processes and a second heating control mode during long idle periods. During idle periods, the system recognizes that heat loss to surrounding components is the primary concern and adjusts the heater temperature accordingly to maintain optimal fixing temperature without excessive energy consumption. The segmentation of control modes allows the system to optimize energy usage based on the specific thermal conditions of each operational state.
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 ensures consistent and accurate toner fixation, preventing defective prints due to temperature fluctuations and maintaining the fixing device at an optimal temperature, thereby improving print quality and reducing the risk of overheating or sticking issues.
Implementation Method 1
a heater inside the heating rotator to heat the medium through the heating rotator
Implementation Method 2
By transmitting heat from a heater to the sheet through, for example, a fixing belt, the fixing device fixes a toner image onto the sheet
Implementation Method 3
Heat is removed from the fixing belt mainly by transfer of heat to sheets passing through the fixing device
Data Source
AI summary
According to one embodiment, a fixing device includes a heating rotator to contact a medium, such as a sheet of paper, on which a toner image has been disposed. A heater is inside the heating rotator to heat the medium. A pressurizing rotator is configured to press against the heating rotator to form a nip through which the medium passes. A controller is configured to drive the heater to heat the heating rotator to a target temperature. The controller is configured to set the target temperature according to a length of a standby time between an end of a first image forming process to a start of a second image forming process after the first image forming process.