Fixing Unit Temperature Difference Detection for Image Formers
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately detecting a shifted-to-one-side state of a recording medium, leading to potential damage of the fixing member due to abnormal temperature increases and decreased productivity, as previous detection methods are prone to errors caused by individual differences in temperature detection elements and variations in heat distribution.
Innovation Solution
An image forming apparatus equipped with a position deviation detection unit that utilizes a combination of temperature detection elements and historical temperature data to accurately determine position deviations, adjusting the detection threshold based on the recording medium's width to prevent temperature-related issues and maintain high productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature detection elements are used to detect shifted-to-one-side state, then position deviation can be detected, but detection precision is low due to individual differences and variations among temperature detection elements
Solution Approach 1:
The patent changes the detection parameter from absolute temperature to temperature difference between two positions. This transformation eliminates the influence of individual differences and variations among temperature detection elements, as only the relative difference matters. The system compares temperature at a first position with temperature at a second position, making the detection immune to individual element characteristics.
Solution Approach 2:
The patent replaces direct mechanical/optical position detection with thermal field-based indirect detection. By using temperature distribution as a proxy for position deviation and incorporating historical temperature data to establish baseline patterns, the system achieves more reliable detection that accounts for thermal inertia and heat distribution variations.
2Measurement precision
If detection is based on change over time in temperature difference, then shifted-to-one-side state can be detected, but detection precision decreases when there is no change from previous job
Solution Approach 1:
The patent performs preliminary action by storing historical temperature data from previous jobs and using it as a reference baseline for current detection. The system pre-processes and retains temperature history information, which is then utilized to compare against current temperature differences, enabling accurate detection even when no change occurs from the previous job.
Solution Approach 2:
The patent implements feedback by continuously comparing current temperature difference measurements with historical temperature patterns. The system uses past temperature data as feedback to establish what normal temperature distribution looks like, allowing it to detect deviations even when absolute temperature changes are minimal, thereby preventing false negatives.
3Temperature
If temperature detection elements are placed on fixing member, then temperature can be monitored, but fixing member may be damaged by abnormal heat accumulation
Solution Approach 1:
The patent applies preliminary anti-action by detecting position deviations before abnormal heat accumulation can damage the fixing member. By monitoring temperature differences at different positions and comparing them against historical data, the system identifies shifted-to-one-side states early, allowing corrective action to be taken before heat damage occurs.
Solution Approach 2:
The patent uses temperature difference as an intermediary indicator rather than directly measuring fixing member temperature. The temperature difference between two positions serves as a mediator that indirectly indicates position deviation and potential heat accumulation risks, allowing the system to detect problems without requiring direct contact with the hottest areas.
4Productivity
If productivity is maintained by continuous operation, then output increases, but fixing member temperature rises due to sheet non-passing area
Solution Approach 1:
The patent enables continuous operation by implementing real-time monitoring of temperature differences and automatic detection of shifted-to-one-side states. This continuous feedback allows the system to maintain productive operation while immediately identifying and responding to conditions that would otherwise cause heat accumulation, ensuring uninterrupted printing while preventing damage.
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
The solution enables precise detection of shifted-to-one-side states, preventing fixing member damage and ensuring consistent productivity by accounting for temperature variations and historical print data, thereby maintaining optimal operating conditions.
Implementation Method 1
a first temperature detection element and a second temperature detection element provided on a fixing member. The first temperature detection element detects temperature of the fixing unit. The second temperature detection element also detects temperature of the fixing unit.
Implementation Method 2
The fixing unit applies heat to the toner image formed on the recording medium so as to fix the toner image to the recording medium.
Data Source
AI summary
An image forming apparatus includes a position deviation detection unit configured to detect a position deviation of a recording medium in a width direction of the recording medium in a current job on a basis of (a) an amount of change over time in a difference between temperature detected by a first temperature detection element and temperature detected by a second temperature detection element and (b) information on temperature distribution on a fixing unit that occurred before the current job.