Fixing Temperature Control in Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in maintaining consistent fixing temperatures during continuous printing, leading to potential image quality deterioration due to the instability caused by the execution of adjustment processes and the positional relationship between temperature sensors and heaters.
Innovation Solution
The apparatus includes a fixing member, a heater, a temperature sensor, a conveyance control portion, a driving control portion, an adjustment processing portion, and a stop processing portion, which control the conveyance and heating processes to ensure the fixing temperature remains within a predetermined range by restricting conveyance until adjustment processes are completed and stopping the process when limitations are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conveyance process is executed in a predetermined cycle during continuous printing, then productivity is improved, but the fixing temperature becomes unstable due to adjustment processes, causing image quality deterioration
Solution Approach 1:
The system performs adjustment processes (such as developing bias adjustment) before they are needed, or schedules them during periods when they will not interfere with the conveyance cycle. The control unit predicts when adjustment processes will be required and schedules them in advance to minimize disruption to the continuous printing process.
Solution Approach 2:
The system implements periodic adjustment processes at predetermined intervals or under specific conditions (such as after a certain number of sheets have been printed). This allows the system to maintain stable operation by periodically recalibrating parameters without continuously interrupting the conveyance process.
2Measurement precision
If the temperature sensor is positioned apart from the contact position to detect temperature, then measurement precision is improved, but the detected temperature does not accurately reflect the fixing temperature at the contact position, causing control inaccuracy
Solution Approach 1:
The control unit uses the temperature detected by the sensor (positioned apart from the contact position) as feedback to adjust heater output. By continuously monitoring the temperature at the sensor position and comparing it to a target temperature, the system can indirectly control the fixing temperature at the contact position through the thermal coupling between these positions.
Solution Approach 2:
The temperature sensor positioned apart from the contact position acts as an intermediary measurement point. Rather than directly measuring the contact position temperature (which would require contact with the sheet), the sensor measures temperature at an intermediate location that correlates with the contact position temperature, allowing indirect but accurate control.
3Manufacturing precision
If adjustment processes are executed during continuous printing, then manufacturing precision is improved, but the conveyance process must be restricted, reducing productivity
Solution Approach 1:
The system performs adjustment processes before they are critically needed, or schedules them during periods when they will not interfere with the conveyance cycle. The control unit predicts when adjustment processes will be required and schedules them in advance to minimize disruption to the continuous printing process.
Solution Approach 2:
The system may perform partial adjustment processes or use multiple smaller adjustments instead of one large adjustment that would require extended interruption. This allows the conveyance process to continue with minimal or no interruption while still achieving the necessary calibration.
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 solution stabilizes the fixing temperature, thereby preventing image quality deterioration and ensuring consistent printing results by synchronizing the conveyance and heating processes with adjustment requirements.
Implementation Method 1
a heater configured to heat the fixing member
Implementation Method 2
a temperature sensor configured to detect a temperature at a detection position separated from a contact position between the fixing member and the transfer surface
Data Source
AI summary
An image forming apparatus includes a temperature sensor, a conveyance control portion, a driving control portion, an adjustment processing portion, and a stop processing portion. The temperature sensor is provided apart from a contact position between a fixing member and a transferred sheet to which a toner image has been transferred. The conveyance control portion continuously executes conveyance processes of conveying the transferred sheet. The driving control portion controls driving of a heater for heating the fixing member so that a temperature detected by the temperature sensor matches a predetermined temperature. The adjustment processing portion restricts the execution of the conveyance process until an adjustment process of adjusting a formation condition of the transferred sheet is completed. The stop processing portion stops the continuous execution of the conveyance processes when the restriction on the execution of the conveyance process continues beyond a predetermined timing.