Fixing Unit Heater Temperature Control via Element Switching
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Solution Overview
Problem
Existing fixing units face challenges in accurately controlling temperature distribution along the heater in a fixing unit, leading to potential damage from temperature rises in non-sheet passing areas, particularly when printing with sheets narrower than the heater width.
Innovation Solution
A fixing unit with a tubular film, a pressure roller, and a heater having first and second heating elements of different lengths, where a detector and controller manage power distribution to maintain accurate temperature control by switching between the heating elements based on detected temperatures and target temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single heating element is used in the heater, then the structure is simple, but temperature distribution along the heater cannot be controlled accurately
Solution Approach 1:
The heater is divided into multiple independent heating elements (first heating element and second heating element) with different lengths in the longitudinal direction. Each heating element can be controlled independently, allowing different temperature zones along the heater. This segmentation enables accurate temperature control in different regions while preventing temperature rise in non-sheet passing portions.
Solution Approach 2:
Different heating elements are designed with different lengths to provide localized heating characteristics. The first heating element has a longer length for heating wider areas, while the second heating element has a shorter length for heating narrower areas. This local quality differentiation allows the heater to adapt to different sheet widths and maintain accurate temperature control in each region.
2Reliability
If the heater operates at high temperature continuously, then fixing performance is improved, but temperature rise in non-sheet passing portions causes damage to fixing members
Solution Approach 1:
The system dynamically selects and switches between different heating elements based on the detected sheet width. When a narrow sheet is detected, the controller switches from the first heating element to the second heating element, which has a shorter length and does not extend into the non-sheet passing portion. This dynamic adaptation maintains high temperature in the sheet passing portion for good fixing performance while preventing temperature rise in the non-sheet passing portion that would damage fixing members.
Solution Approach 2:
The controller detects the sheet width and uses this feedback information to determine which heating element to activate. This feedback mechanism ensures that the heating element configuration matches the actual sheet being processed, preventing unnecessary heating in non-sheet passing areas while maintaining optimal temperature for fixing the current sheet.
3Measurement precision
If heating elements are switched frequently, then temperature control accuracy is improved, but control system complexity increases
Solution Approach 1:
The control system is segmented into simple on/off control logic for each heating element based on sheet width thresholds. Rather than implementing complex continuous control, the system uses discrete switching between pre-configured heating elements, simplifying the control algorithm while maintaining temperature control accuracy through appropriate element selection.
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 enables precise temperature control, preventing excessive temperature rises in non-sheet passing areas and ensuring the longevity of fixing unit components.
Implementation Method 1
a heater configured to heat the film and arranged in an interior space of the film, the heater including a first heating element and a second heating element
Implementation Method 2
a detector configured to detect a temperature of the heater
Data Source
AI summary
A fixing unit includes a tubular film, a pressure roller, a heater including a first heating element and a second heating element, a detector configured to detect a temperature of the heater, a switcher configured to switch which of the first heating element and the second heating element is supplied power from a power supply, and a controller configured to control the switcher. The controller is configured to execute a first control of determining a first electric energy and a second electric energy based on the temperature of the heater detected by the detector and a target temperature of the heater, and a second control of causing the switcher to switch between a state in which power is supplied to the first heating element by the first electric energy and a state in which power is supplied to the second heating element by the second electric energy.