Image Forming Apparatus Comparator Supply for Fuser Overheat Detection
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Solution Overview
Problem
The provision of a dedicated power supply for inputting a reference voltage to a comparator in image forming apparatuses increases costs.
Innovation Solution
An image forming apparatus is designed without a dedicated power supply for the comparator, utilizing a first sensor to detect a physical quantity and output a sensor voltage, which is compared with a reference voltage, and a power supply that turns on or off based on operational modes to generate specific voltages for sensor and reference voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated power supply is provided to input reference voltage to the comparator, then the overheating detection function is reliable, but the manufacturing cost increases
Solution Approach 1:
The patent merges the reference voltage power supply function with the existing sensor power supply circuit. The same power supply circuit that provides power to the temperature sensor is also used to generate the reference voltage for the comparator, eliminating the need for a separate dedicated power supply and reducing manufacturing costs while maintaining detection reliability
Solution Approach 2:
The power supply circuit is designed to serve multiple functions: it powers the temperature sensor, generates the reference voltage for the comparator, and operates in different modes (normal and power-saving) based on system requirements. This multi-functional design reduces component count and manufacturing complexity
2Stability of the object's composition
If a dedicated power supply is provided for the comparator reference voltage, then the voltage stability is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple power supply functions into a single circuit that generates both sensor operating voltage and comparator reference voltage from the same power source, reducing circuit complexity while maintaining voltage stability through shared reference generation
Solution Approach 2:
The power supply circuit dynamically changes its output parameters based on operational mode, providing stable reference voltage during normal operation and transitioning to a power-saving mode with reduced power consumption when overheating detection is less critical, thereby managing voltage stability requirements across different operating conditions
Data Source
AI summary
An image forming apparatus includes a first sensor, a first comparator, and a first power supply. The first sensor is configured to detect a physical quantity of the image forming apparatus and output a corresponding first sensor voltage. The first comparator is configured to receive the first sensor voltage and a first reference voltage, compare them, and output a first output signal when the first sensor voltage exceeds the first reference voltage. The first power supply is configured to be turned on or off depending on whether the image forming apparatus is in a first mode or a second mode that consumes less power than the first mode. Thereby, the first power supply outputs a specific voltage in the first mode, and does not output the specific voltage in the second mode. The specific voltage is used to generate the first sensor voltage and the first reference voltage.