Fanless Fixing Device Thermal Management via Exit Port Dynamics
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses rely on fans for temperature control, which hinder size reduction and lead to inefficient use of thermal energy due to forced cooling of the entire device.
Innovation Solution
A fixing device without a fan, utilizing a closing portion with a rotation member and a separating unit that changes its state based on temperature sensing or elapsed time to control the nip region, allowing for efficient thermal energy usage by adjusting the exit port's openness and temperature retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fan is used for temperature control in the fixing device, then temperature regulation is achieved, but the device size increases and thermal energy efficiency deteriorates
Solution Approach 1:
The patent removes the fan from the fixing device structure, extracting the unnecessary cooling component that caused size increase. Instead of using a fan for temperature control, the invention relies on natural convection and selective opening/closing of the exit port to regulate temperature, thereby reducing device complexity while maintaining temperature regulation functionality.
Solution Approach 2:
The fixing device uses its own thermal energy and natural convection currents to regulate temperature without external mechanical intervention. The heating member and pressing member generate heat that naturally circulates within the casing, and the exit port can be opened or closed to control heat escape, allowing the system to self-regulate temperature without a fan.
2Temperature
If a fan is used for cooling in the fixing device, then temperature control is achieved, but thermal energy efficiency deteriorates due to forced cooling of the entire device
Solution Approach 1:
Instead of forcing cooling throughout the entire device, the invention applies cooling control locally at the exit port. By selectively opening or closing the exit port, the system allows heat to escape only when necessary and maintains warmth in the fixing chamber when needed, thereby improving thermal energy efficiency compared to uniform forced cooling.
Solution Approach 2:
The exit port is opened and closed periodically based on temperature conditions and operational requirements. This periodic control allows the device to retain thermal energy during operation and release it when needed, rather than continuously forcing cooling, thereby reducing energy loss and improving thermal efficiency.
3Loss of energy
If the exit port is kept closed to retain temperature, then thermal energy efficiency improves, but the device cannot discharge recording paper sheets
Solution Approach 1:
The exit port transitions from a static closed state to a dynamic system that can open and close based on operational needs. During paper sheet discharge, the exit port opens to allow sheets to exit while maintaining temperature retention during operation. This dynamic control resolves the contradiction between energy retention and paper discharge capability.
Solution Approach 2:
The exit port is opened in advance before paper sheet discharge is required, allowing smooth discharge operation. After discharge, the port is closed to retain temperature for the next operation. This preliminary opening action ensures both discharge capability and thermal efficiency without conflict.
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 efficient thermal energy use, reduces warm-up time, and minimizes temperature loss, resulting in energy savings and cost reduction while maintaining device performance.
Implementation Method 1
a heating member for heating the recording paper sheet
Implementation Method 2
a heating member for heating the recording paper sheet
Implementation Method 3
an elastic member arranged on a side opposed to the opposed member with the rotation member therebetween for biasing the opposed member to press the opposed member against the rotation member
Implementation Method 4
a shape-memory material arranged on the side opposed to the rotation member with the first opposed portion therebetween for pressing the opposed member, against a biasing force of the elastic member, to separate the opposed member from the rotation member in accordance with a change in temperature
Data Source
AI summary
A fixing device for fixing a toner image onto a recording paper sheet includes a heating member for heating the recording paper sheet, a pressing member for applying a pressure by forming contact with the heating member, a casing accommodating the heating member and the pressing member, and provided with an exit port for discharging the recording paper sheet, and a closing portion arranged at the exit port for keeping a temperature of the casing. The closing portion has a rotation member, and an opposed member forming a nip region together with the rotation member. A separating unit for changing at least a part of the closing portion from a closed state to an open state.