Image Forming Apparatus Controller Adjusts Sheet Feeding Timing
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Solution Overview
Problem
In electrophotographic printers, the temperature rise at the end portions of the heating member is slower than at the central portion, leading to delayed printing starts and potential fixing defects due to insufficient heat accumulation, complicating control and reducing printing speed.
Innovation Solution
An image forming apparatus with a controller that adjusts the sheet feeding timing based on the area of the image at the sheet's end portions, allowing for earlier sheet feeding by setting a shorter predetermined period when the image area is small, and optimizing heat accumulation by adjusting the heating process to reach a fixing temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feeding timing of the sheet is accelerated to increase printing speed, then productivity is improved, but fixing defects may occur due to insufficient heat accumulation in the heating member
Solution Approach 1:
The controller performs preliminary heating of the heating member to a predetermined temperature before sheet feeding starts, ensuring that heat is accumulated in advance. This preliminary action allows the system to accelerate sheet feeding without causing fixing defects, as the heating member is already prepared with sufficient heat.
Solution Approach 2:
The system dynamically adjusts the feeding timing of sheets based on the temperature of the heating member. When the heating member reaches the predetermined temperature, the controller accelerates sheet feeding; otherwise, it delays feeding. This dynamic adjustment resolves the contradiction between printing speed and fixing quality.
2Reliability
If the temperature of the end portions of the heating member is increased to reach fixing temperature, then fixing quality is improved, but the time required for heating increases, reducing printing speed
Solution Approach 1:
The controller monitors the temperature specifically at the end portions of the heating member, which are the coldest regions. By focusing heating control on these critical local areas, the system ensures fixing quality at the most vulnerable spots without unnecessarily heating the entire heating member to excessive temperatures, thus optimizing the balance between fixing quality and heating time.
Solution Approach 2:
The system uses temperature detection at the end portions of the heating member to provide feedback to the controller. Based on this feedback, the controller adjusts the heating control and sheet feeding timing dynamically. This closed-loop control ensures that the heating member reaches the necessary temperature for fixing quality while minimizing unnecessary heating time.
3Reliability
If the sheet feeding timing is decided based on the temperature of the end portions of the heating member, then fixing quality is ensured, but the control becomes complicated
Solution Approach 1:
The controller changes the parameter of sheet feeding timing based on the detected temperature of the heating member. By using a clear temperature threshold as the decision parameter, the control logic remains relatively simple while ensuring fixing quality. The system adjusts the feeding timing parameter dynamically based on temperature conditions without requiring complex control algorithms.
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
Simplifies control and accelerates sheet feeding, enabling rapid printing without waiting for full heat accumulation, while minimizing fixing defects by tailoring the heating and feeding processes to the image area and sheet characteristics.
Implementation Method 1
a halogen heater configured to heat the heating roller
Implementation Method 2
a heating roller configured to heat a sheet
Data Source
AI summary
A controller of an image forming apparatus executes acquisition processing of acquiring an area of an image which exists in a predetermined region of a first page where a developer image is first to be formed, heating processing of heating a heating member such that a temperature of the heating member reaches a fixing temperature, and feeding processing of starting feed of a sheet to a process unit after a predetermined period of time elapses from a predetermined timing after a start of print processing. The predetermined region is laid at both end portions in a width direction of the first page. In a case where the area of the image is equal to or smaller than a predetermined value, the controller sets the predetermined period of time in the feeding processing shorter as compared with a case where the area of the image is larger than the predetermined value.