Image Forming Fixing Control for Timely Sheet Conveyance
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Solution Overview
Problem
In existing image forming apparatuses, the sheet feeding permission temperature is set based on the number of sheets to be printed, leading to unnecessary delays in conveying start timing, especially during continuous printing, which can result in delayed fixing of images due to insufficient heat retention in the fixing unit.
Innovation Solution
The controller determines the appropriate conveying processing (first, second, or third) based on multiple printing conditions, including sheet length, thickness, external temperature, conveying speed, and printing mode, to optimize the conveying start timing and prevent delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet feeding permission temperature is set high to ensure sufficient fixing temperature, then the fixing quality is improved, but the conveying start timing is unnecessarily delayed
Solution Approach 1:
The sheet feeding permission temperature is dynamically adjusted based on the detected fixing unit temperature. When the fixing unit temperature is high, a higher sheet feeding permission temperature is set to ensure quality. When the fixing unit temperature is low, a lower sheet feeding permission temperature is set to avoid unnecessary delays. This dynamic adjustment resolves the contradiction by adapting the temperature threshold to actual thermal conditions.
Solution Approach 2:
The patent changes the parameter of sheet feeding permission temperature based on multiple factors including fixing unit temperature, number of sheets, and external temperature. By making this parameter variable rather than fixed, the system can optimize both fixing quality and timing responsiveness under different operating conditions.
2Productivity
If the conveying start timing is advanced to reduce output time, then the productivity is improved, but the fixing unit temperature may be insufficient causing fixing failures
Solution Approach 1:
The system uses feedback from the fixing unit temperature detection to determine the appropriate sheet feeding permission temperature. The temperature detection unit continuously monitors the fixing unit temperature, and this feedback information is used to adjust the conveying start timing. This ensures that sheets are conveyed only when the fixing unit has reached a suitable temperature, preventing fixing failures while optimizing output time.
Solution Approach 2:
The system performs preliminary temperature detection and evaluation before initiating sheet conveyance. By detecting the fixing unit temperature in advance and evaluating whether it meets the required threshold, the system can prepare for optimal conveying timing without rushing into premature operation that would cause fixing failures.
3Loss of time
If the sheet feeding permission temperature is set low to start conveying early, then the loss of time is reduced, but the fixing strength is insufficient
Solution Approach 1:
The sheet feeding permission temperature is dynamically set based on the detected fixing unit temperature rather than using a fixed low threshold. When the fixing unit temperature is high, the permission temperature can be set higher without causing delays. When the fixing unit temperature is low, the permission temperature is set lower to enable earlier conveyance. This dynamic approach prevents both unnecessary delays and insufficient fixing strength.
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 timely conveying to maintain fixing strength and reduce power consumption by advancing or delaying the start timing according to specific conditions, thereby preventing fixing failures and shortening the first paper output time.
Implementation Method 1
a fixing unit 4 that executes heat fixing on the sheet S
Implementation Method 2
a temperature detector 46A, 46B that detects a temperature of the fixing unit 4
Data Source
AI summary
An image forming apparatus includes: an image forming unit; a conveying unit; a fixing unit including a heater and a temperature detector; and a controller. The controller is configured to execute: first conveying processing of controlling the conveying unit to start conveying the sheet after a first time period has elapsed since the temperature detected by the temperature detector reaches a first temperature, second conveying processing of controlling the conveying unit to start conveying the sheet in response to the temperature reaches the first temperature, third conveying processing of controlling the conveying unit to start conveying the sheet in response to the temperature reaches a second temperature that is lower than the first temperature, and determination processing of determining, according to a plurality of printing conditions, which of the first conveying processing, the second conveying processing, and the third conveying processing is to be executed.