Fixing Device Heat Source Synchronization for Toner Quality
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses experience quality issues due to deviations in the turning-on/off cycle of the heat source, leading to inconsistent temperature control at the nip portion, resulting in poor gloss and irregularities in toner fixing during continuous image-forming jobs.
Innovation Solution
The control cycle of the heat source is synchronized with the passage timing of the recording medium through the nip portion, ensuring the same number of turn-ons for all sheets, thereby maintaining consistent temperature and preventing quality deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the heat source is controlled using a conventional duty-based turning-on/off cycle, then energy saving is achieved, but temperature consistency at the nip portion deteriorates
Solution Approach 1:
The control cycle is set in advance based on the conveyance speed and sheet interval, so that the heat source turns on at the optimal timing before the sheet reaches the nip portion. This preliminary timing adjustment ensures consistent temperature at the nip while maintaining energy efficiency.
Solution Approach 2:
The control cycle is dynamically adjusted according to the conveyance speed and sheet interval. By making the control cycle adaptive to changing operating conditions, the system maintains optimal temperature consistency across different printing speeds and sheet densities.
2Ease of operation
If the control cycle does not synchronize with sheet passage timing, then control simplicity is maintained, but fixing quality deteriorates
Solution Approach 1:
The system uses feedback from the conveyance speed detection and sheet interval measurement to automatically adjust the control cycle timing. This feedback mechanism maintains fixing quality without requiring manual intervention, preserving operational simplicity while achieving precise temperature control.
Solution Approach 2:
The mechanical synchronization problem is replaced by an electronic control system that calculates and adjusts the control cycle based on detected conveyance parameters. This substitution maintains simplicity of operation while achieving precise synchronization between heating and sheet passage.
3Temperature
If the heat source turns on frequently, then temperature stability is improved, but energy consumption increases
Solution Approach 1:
The heat source operates in periodic cycles that are optimized based on the sheet passage timing. By controlling the period and duration of heating cycles to match the actual need (sheet presence at nip), the system achieves temperature stability without unnecessary energy consumption during idle periods.
Solution Approach 2:
The control cycle parameters (duration, frequency, timing) are changed according to operating conditions such as conveyance speed and sheet interval. This dynamic parameter adjustment allows the system to maintain temperature stability while adapting energy consumption to actual processing needs.
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 toner fixing quality by maintaining the target temperature at the nip portion, preventing both insufficient and excessive fixing, and reducing temperature-related irregularities, thus enhancing the overall image quality and extending the lifespan of the heat source.
Implementation Method 1
high speed heating is realized using a heat source, such as a halogen heater or a graphite heater, which heats the fixing member with radiant heat
Implementation Method 2
a fixing device of a contact heating system, for example, a heat roller system, a film heating system, and an electromagnetic induction heating system
Implementation Method 3
a temperature-detecting unit detects the temperature of the fixing member based on temperature information from the temperature-detecting unit
Implementation Method 4
a fixing device of a contact heating system... heats the fixing member... makes pressure-contact with the fixing member to form a nip portion
Data Source
AI summary
A fixing device includes a rotatable fixing member that heats a surface of a recording medium on which an unfixed image is carried, a rotatable pressing member that makes pressure-contact with the fixing member to form a nip portion therebetween, a heat source that heats the fixing member, a temperature detecting unit that detects a temperature of the fixing member, and a temperature control unit that controls turning-on/off the heat source in accordance with a predetermined duty for a predetermined control cycle in a turning-on/off cycle, based on input temperature information. The temperature control unit, during execution of a continuous image-forming job for continuously forming images on a plurality of recording media, sets the control cycle and a space between the recording media to be conveyed to the nip so that a number of turn-ons of the heat source is the same for all the recording media.