Variable Heat Capacity Fixing Apparatus for Image Formers
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Solution Overview
Problem
Existing fixing apparatuses in image forming devices face challenges in shortening first printout time (FPOT) and energy saving due to excessive temperature rise in non-sheet passing portions, especially when dealing with varying sizes of recording materials, as increasing heat capacity to suppress this rise hinders further FPOT reduction.
Innovation Solution
A fixing apparatus with a cylindrical film, a thin and long heater, and a heat transfer member with varying heat capacity along its length, where the heat transfer member has a larger capacity near the ends of standard-sized recording materials compared to the center, effectively reducing non-sheet passing portion temperature rise while maintaining quick start performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat transfer members with high thermal conductivity are arranged on heating member surfaces to suppress non-sheet passing portion temperature rise, then temperature control is improved, but heat capacity of the entire heat transfer member must be set high which prevents further FPOT shortening
Solution Approach 1:
The heat transfer member is designed with non-uniform thickness where the first portion (corresponding to non-sheet passing regions) has greater thickness than the second portion (corresponding to sheet passing regions). This creates localized heat capacity distribution that suppresses temperature rise in non-sheet passing portions without increasing overall heat capacity, thereby maintaining quick startup performance while solving the temperature control problem.
2Stability of the object's composition
If heat capacity of heat transfer member is increased to suppress non-sheet passing portion temperature rise, then temperature stability is improved, but warming-up time increases which hinders FPOT reduction
Solution Approach 1:
The heat transfer member features variable thickness with the first portion having greater thickness than the second portion. This local quality differentiation provides targeted thermal mass in non-sheet passing regions for temperature stability, while keeping sheet passing regions lightweight for rapid heating, thus achieving temperature stability without extending warming-up time.
Solution Approach 2:
The heat transfer member is effectively segmented into two functional portions: the first portion with greater thickness for thermal stability in non-sheet passing regions, and the second portion with smaller thickness for rapid heating in sheet passing regions. This segmentation allows independent optimization of thermal properties in different zones.
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 simultaneously suppresses non-sheet passing portion temperature rise and maintains quick start performance, allowing for efficient fixing of images on various sized recording materials without prolonging warming-up times.
Implementation Method 1
a heater that contacts an inner surface of the film... heats a recording material having a toner image formed thereon at the nip portion
Implementation Method 2
a heat transfer member configured to contact, along a longitudinal direction of the heater, a surface opposite to a surface of the heater that contacts the inner surface of the film
Implementation Method 3
a pressing member forming a nip portion with the heater via the film, heats a recording material having a toner image formed thereon at the nip portion
Data Source
AI summary
A fixing apparatus for fixing an image on a recording material includes a cylindrical film, a heater configured to heat the film, the heater contacting an inner surface of the film, a heat transfer member configured to contact a surface opposite to a surface of the heater that contacts the inner surface of the film, and a support member configured to support the heater. A heat capacity per unit length of a first portion that is a portion of the heat transfer member corresponding to a region near an end of the recording material in a width direction among non-sheet passing region is larger than that of a second portion that is a portion of the heat transfer member corresponding to a center of the recording material in the width direction.