Heating Roller Power Control for Rapid Warm-up
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Solution Overview
Problem
Conventional image forming apparatuses face limitations in reducing the first print out time (FPOT) due to the slow heating of the heating roller, as the existing power control methods can cause excessive current flow and flicker characteristics, leading to inefficient temperature increase and requiring the control unit to be initialized before heating can commence.
Innovation Solution
A power control method that gradually increases the source power supplied to the heating roller before the image forming apparatus is fully initialized, allowing the heating roller to reach the fixing target temperature quickly while minimizing flicker characteristics by supplying maximum power after a specific elapsed time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If maximum power is supplied to the heating resistor to rapidly increase the heating roller's surface temperature, then the first print out time is reduced, but excessive current flows through the heating resistor causing circuit damage and flicker characteristics
Solution Approach 1:
The patent applies preliminary action by gradually increasing the power supply to the heating resistor in predetermined stages before reaching maximum power. This staged approach allows the heating roller to warm up progressively without causing excessive current flow that would damage the circuit or create flicker characteristics, thus resolving the contradiction between reducing first print out time and maintaining circuit stability.
2Reliability
If the control unit is fully initialized before heating the heating roller, then system stability is ensured, but the first print out time increases due to the sequential operation requirement
Solution Approach 1:
The patent enables the heating operation to commence before the control unit is fully initialized by implementing preliminary heating action. The power supply unit can gradually increase power to the heating resistor independently of the control unit's initialization status, allowing the heating roller to reach operating temperature in parallel with control unit initialization, thus reducing first print out time while maintaining system stability through the staged power increase mechanism.
3Speed
If a heating resistor with lower threshold resistance is used to supply more power, then the heating roller temperature increases more rapidly, but higher current flows causing excessive heat and flicker characteristics
Solution Approach 1:
The patent applies dynamics by implementing a dynamic power supply control mechanism that gradually increases the power level in predetermined stages rather than applying maximum power immediately. This dynamic adjustment allows the system to optimize heating speed while preventing excessive current flow and flicker characteristics, as the power increase is controlled and progressive rather than static and abrupt.
Solution Approach 2:
The patent implements periodic action through predetermined time intervals between power increase stages. The power supply unit increases power in discrete steps with specific time delays, allowing the heating roller to warm up progressively. This periodic power adjustment enables rapid heating while preventing harmful effects of excessive current by spacing out the power increases over time.
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 enables the heating roller to rapidly reach the fixing target temperature, reducing the FPOT and allowing printing to begin sooner, even before the control unit is fully initialized, while preventing overheating or underheating issues.
Implementation Method 1
a voltage (Vin) 110 illustrated is applied to a heating resistor from an external source, causing a current (Ir) 120 to flow through the heating resistor
Data Source
AI summary
An image forming apparatus includes a power supply unit that controls a level of electrical power supplied to the heating lamp during a warm-up of the heating unit that involves at least a first warm-up stage. During the first warm-up stage, when power begins to be supplied to the heating lamp, the power supply unit gradually increases a level of power supplied to the heating lamp from zero to a defined supply level according to a phase control of an alternating current (AC) of the source power. If a second warm-up stage is included, during the second warm-up stage, the power supply unit may maintain the level of power supplied to the heating lamp at the defined supply level until the measured surface temperature of the heating unit has reached a defined target temperature.