Image Forming Apparatus Temperature Control via Coverage Ratio History
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Solution Overview
Problem
The challenge is to conserve energy while maintaining or improving the gloss of toner images in image forming apparatuses, particularly when the thermal capacity of the fixing member is reduced, leading to fluctuations in surface temperature based on the history of toner images printed.
Innovation Solution
An image forming apparatus with a fixing portion that includes a heater, a temperature detecting portion, and a power control mechanism. The apparatus acquires toner coverage ratio information and adjusts the power supplied to the heating element based on a correction factor, ensuring consistent temperature control and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the thermal capacity of the fixing member is decreased to conserve energy, then energy consumption is reduced and first-print-out-time is decreased, but the surface temperature of the fixing member fluctuates more depending on the history of toner images
Solution Approach 1:
The system performs preliminary acquisition of toner image information (coverage ratio) before the fixing process, and pre-calculates the appropriate target temperature based on the expected toner coverage. This allows the fixing member to be pre-heated to the correct temperature before actual fixing begins, preventing temperature fluctuations caused by varying toner loads.
Solution Approach 2:
The system implements a feedback mechanism where the coverage ratio of toner images is continuously monitored and used to adjust the target temperature of the fixing member. The temperature control unit receives feedback about the actual toner coverage and modifies heating power accordingly, maintaining stable surface temperature despite changes in thermal capacity or printing history.
2Loss of time
If the thermal capacity of the fixing member is decreased, then the first-print-out-time is reduced, but the temperature control becomes more sensitive to toner image history
Solution Approach 1:
The system acquires toner image information and determines coverage ratios before the fixing process begins. This preliminary action allows the system to pre-calculate target temperatures and prepare heating control strategies in advance, enabling rapid response when printing starts without requiring complex real-time adjustment mechanisms.
Solution Approach 2:
The system dynamically changes the target temperature parameter based on the coverage ratio of toner images. By adjusting this key parameter according to actual printing conditions, the system simplifies temperature control logic while maintaining effectiveness, avoiding the need for complex control algorithms.
3Productivity
If continuous printing with high toner coverage is performed, then the fixing member temperature drops, but energy conservation becomes difficult to maintain
Solution Approach 1:
The system calculates coverage ratios for continuous printing jobs in advance and determines the appropriate target temperature before printing begins. This allows the system to maintain optimal temperature with minimal energy input by anticipating the thermal load from high-coverage pages, rather than reacting to temperature drops after they occur.
Solution Approach 2:
The system implements feedback control where coverage ratio information from continuous printing jobs is used to continuously adjust the target temperature. This ensures energy conservation by maintaining the minimum necessary temperature for the actual printing workload, preventing both overheating and insufficient heating during continuous operation.
4Loss of energy
If the fixing member temperature rises due to low toner coverage, then excessive heat is supplied, but gloss improvement becomes unnecessary
Solution Approach 1:
The system determines the coverage ratio before fixing and pre-calculates the appropriate target temperature. This preliminary determination allows the system to set the correct temperature in advance, preventing both excessive heating on low-coverage pages and insufficient heating on high-coverage pages, ensuring consistent gloss quality while minimizing energy waste.
Solution Approach 2:
The system dynamically changes the target temperature parameter based on coverage ratio measurements. By adjusting this parameter according to actual toner coverage, the system eliminates excessive heat supply on low-coverage pages while ensuring adequate heating on high-coverage pages, maintaining gloss consistency and reducing energy loss simultaneously.
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 influence of toner image history on temperature control, allowing for both energy conservation and improved gloss by stabilizing the surface temperature of the fixing member.
Implementation Method 1
a fixing portion which includes a heater constituted of a substrate and a heating element disposed on the substrate, and fixs a toner image formed on a recording material to the recording material using the heat of the heater
Implementation Method 2
a compact thermistor, which contacts or adheres to the heating element, so that the temperature of the recording material remains constant
Data Source
AI summary
When an image forming portion continuously forms a toner image on a plurality of recording materials, an acquiring portion, which acquires information on the toner on the recording materials from the image information, acquires a coverage ratio, which is a ratio of an image portion, that is, a toner laid-on portion in a predetermined region of the recording material, with respect to the predetermined region, for a plurality of recording materials, and an power control portion controls the power supplied to a heating element of a heater in a fixing portion for each of the plurality of recording materials based on a control target temperature, which is determined by correcting a reference target temperature in the predetermined region by a correction amount reflecting the history of the coverage ratio in the plurality of recording materials.