Fuser Mode Switching for Narrow-to-Wide Sheet Printing
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Solution Overview
Problem
In image forming apparatuses, the accumulation of heat in non-sheet passing regions of the fixing device leads to high temperatures, causing hot offset when wide-width sheets are printed after narrow-width sheets, necessitating prolonged cooling times that prolong the overall printing process.
Innovation Solution
The image forming apparatus employs a controller to switch between first and second printing modes based on sheet width, adjusting conveying speeds to minimize cooling times by optimizing the total time required for printing both narrow and wide-width sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If narrow-width sheets are continuously printed in the fixing device, then the non-sheet passing region reaches high temperature due to heat accumulation, but this causes hot offset when wide-width sheets are subsequently printed, requiring prolonged cooling times
Solution Approach 1:
The controller predicts the temperature rise in the non-sheet passing region before wide-width sheets are printed by monitoring the cumulative heating amount from previously printed narrow-width sheets. This preliminary prediction enables proactive cooling control to prevent hot offset before it occurs.
Solution Approach 2:
The system uses feedback from the cumulative heating amount calculation to dynamically adjust cooling control. The controller continuously monitors the heating state and adjusts cooling intervention based on the predicted temperature rise, creating a closed-loop control system that prevents hot offset while minimizing unnecessary cooling.
2Object-affected harmful factors
If cooling time is extended to prevent hot offset, then hot offset is suppressed, but the total printing time increases
Solution Approach 1:
The controller performs preliminary prediction of temperature rise using cumulative heating amount data before wide-width sheets are printed. This allows cooling to be initiated at the optimal moment - just enough to prevent hot offset without excessive cooling time, thereby minimizing the impact on total printing time.
Solution Approach 2:
The system dynamically changes cooling control parameters based on the predicted temperature rise. Instead of using fixed cooling times, the controller adjusts cooling intensity and duration according to the actual heating state, achieving hot offset prevention with minimal time loss.
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 the overall time needed to complete printing on both narrow and wide-width sheets by efficiently managing heat accumulation and preventing hot offset, thereby enhancing printing efficiency.
Implementation Method 1
a fixing device including a heater and for heating a toner image, carried on a recording material, by the heater
Data Source
AI summary
An image forming apparatus includes a fixing device and a controller. When a job in which the image is printed on a narrow sheet is a first printing job, a job which the image is printed on a wide sheet is a second printing job, a time when cooling of a heater of the fixing device is executed after the first printing job is ended is a cooling time, and a time obtained by summing the cooling time and a print completion time is a total time, the controller executes the first printing job by an operation in a printing mode in which the total time becomes shorter between a total time when the controller executes the first printing job by the operation in the first printing mode and a total time when the controller executes the first printing job by the operation in the second printing mode.