Heating Roller Temperature Control for Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in reducing waiting time for raising the fixing temperature from one page to the next, especially when the target fixing temperatures differ significantly, as they cannot effectively utilize the sheet interval period for temperature increment when the first page is the initial page being printed.
Innovation Solution
An image forming apparatus that acquires image information for each page, determines target fixing temperatures, and controls the heating roller's surface temperature by reserving periods during the thermal fixing operation and sheet interval to raise the temperature incrementally, ensuring the surface temperature reaches the target temperature before starting the thermal fixing of the succeeding page, even when the difference between target temperatures is large.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target fixing temperature is raised significantly for the succeeding page, then the fixing quality is improved, but the waiting time during the sheet interval period increases
Solution Approach 1:
The patent applies preliminary action by starting to raise the heating roller's surface temperature during the thermal fixing operation of the current page, before the sheet interval period begins. This allows the temperature to be partially increased in advance, reducing the waiting time needed during the sheet interval to reach the target temperature for the succeeding page.
Solution Approach 2:
The patent segments the temperature raising process into two phases: (1) temperature increase during the thermal fixing operation period, and (2) remaining temperature increase during the sheet interval period. This segmentation allows the temperature control to be optimized across both periods, reducing the total waiting time while ensuring the target temperature is reached.
2Use of energy by moving object
If the target fixing temperature is changed for each page according to image characteristics, then power consumption is reduced, but the temperature control complexity increases
Solution Approach 1:
The patent implements dynamic temperature control by adjusting the target fixing temperature for each page based on image characteristics (text images vs. non-text images). The system dynamically determines whether to apply a first target temperature (for text images) or a second target temperature (for non-text images), optimizing power consumption while adapting to varying printing requirements.
Solution Approach 2:
The patent uses feedback by analyzing image characteristics (such as image density, area ratio, or presence of text) to determine the appropriate target fixing temperature for each page. This feedback mechanism allows the system to automatically adjust temperature settings based on the actual printing requirements, reducing power consumption without manual intervention.
3Loss of time
If the sheet interval period is extended to raise the temperature, then the waiting time is reduced, but the printing productivity decreases
Solution Approach 1:
The patent maintains continuity of useful action by utilizing the thermal fixing operation period (which would otherwise be idle for temperature adjustment) to raise the heating roller's temperature. This allows temperature increase to occur concurrently with the printing process, eliminating the need to extend the sheet interval period and thereby maintaining printing productivity.
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 reduces waiting time and improves productivity by allowing the temperature to be raised efficiently during the sheet interval, even when the difference between target fixing temperatures is substantial, thereby optimizing power usage and printing efficiency.
Implementation Method 1
thermally fixing the toner images by passing the recording sheet through a fixing position on a heating roller
Implementation Method 2
the temperature control unit reserves part or all of a first period, and a second period... the reserved periods serving as periods for raising the surface temperature of the heating roller
Data Source
AI summary
An image forming apparatus forming toner images sequentially on recording sheets transported at intervals, and thermally fixing the toner images by passing the recording sheets through a fixing position on a heating roller. The target fixing temperature is determined according to information of an image on each page. When a first fixing temperature for a given page is higher than a second fixing temperature for the succeeding page and the difference therebetween is greater than a predefined value, part or all of a first period, during which the thermal fixing operation for the given page is performed, and a second period, which corresponds to an interval between the two pages, are reserved for raising the surface temperature by the difference, and temperature control is performed during the reserved periods such that the surface temperature reaches the second temperature before the thermal fixing operation for the succeeding page starts.