Fixing Unit Temperature Control for Power and Image Quality
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Solution Overview
Problem
Image forming apparatuses face challenges in reducing power consumption while preventing image defects like cold offset, as existing solutions fail to adjust heating temperatures effectively with varying toner weights per unit area across consecutive pages.
Innovation Solution
An image forming apparatus that sets the target temperature of the fixing unit based on the image density of each page and corrects temperatures according to the image densities of subsequent pages to maintain optimal heating conditions, reducing power consumption and preventing cold offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the heater control temperature is adjusted according to the weight per unit area of toner on the current page only, then power consumption is reduced, but image defects such as cold offset occur when toner weight changes greatly between consecutive pages
Solution Approach 1:
The patent applies preliminary action by setting the heater control temperature for the current page based on the toner weight of the next page in advance. The control unit predicts the toner weight of subsequent pages from image data and adjusts the heater temperature beforehand to prevent cold offset when toner weight increases significantly. This ensures the heating system is prepared before the actual printing occurs, maintaining image quality while optimizing power consumption.
Solution Approach 2:
The patent implements feedback by continuously monitoring image data and using it to dynamically adjust heater control temperatures. The control unit receives image data, predicts toner weight for current and subsequent pages, and adjusts the heater temperature accordingly. This closed-loop control ensures that the heating system responds appropriately to varying toner weights, preventing both excessive power consumption and image defects.
2Reliability
If the heater target temperature is increased to prevent cold offset, then image quality is maintained, but power consumption increases excessively when toner weight is small
Solution Approach 1:
The patent applies dynamics by making the heater control temperature variable rather than fixed. The control unit dynamically adjusts the target temperature based on the predicted toner weight of the current and next pages. When toner weight is small, the temperature is reduced to save power; when toner weight increases (especially on the next page), the temperature is raised in advance to prevent cold offset. This dynamic adjustment optimizes both energy efficiency and image quality.
Solution Approach 2:
The patent implements parameter changes by modifying the heater control temperature parameter according to toner weight conditions. The control unit changes the target temperature parameter based on image data analysis, setting it to the minimum temperature required for effective fixing when toner weight is low, and raising it when toner weight increases. This parameter adjustment resolves the contradiction between power consumption and image quality by adapting the temperature to actual printing 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 effectively reduces power consumption while preventing cold offset by dynamically adjusting the target temperature based on image density information, ensuring consistent heating across pages with varying toner weights.
Implementation Method 1
a fixing unit configured to heat the recording material where the unfixed toner image is formed while conveying the recording material using a nip portion, and to fix the unfixed toner image on the recording material
Data Source
AI summary
An image forming apparatus configured to form a toner image on a recording material, includes: an image forming unit configured to form a unfixed toner image on the recording material; a fixing unit configured to heat the recording material where the unfixed toner image is formed while conveying the recording material using a nip portion, and to fix the unfixed toner image on the recording material; and a control unit configured to perform control so that temperature of the fixing unit is maintained in target temperature, with the target temperature (Tn) of a n'th page in consecutive printing being set to the highest temperature of the target temperatures (Tn to Tn+k) according to each of image densities (Dn to Dn+k) at (n to (n+k))'th pages, where integer k≦1.