Heater Control Timing for Image Forming Apparatus
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Solution Overview
Problem
Existing heating systems in image forming apparatuses take a long time to reach predetermined temperatures due to inefficient power supply management, which prolongs the First Print Out Time (FPOT).
Innovation Solution
A heating system that includes a first heater, a current sensor, and a controller, which determines the optimal timing for energizing and de-energizing the heater based on the alternating current waveform, using a switch to manage power supply efficiently and shorten the time to reach target temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If voltage is applied continuously to the heater during a half cycle of alternating current, then the heater reaches higher temperature faster, but the power supply consumption increases
Solution Approach 1:
The patent applies periodic voltage to the heater in two distinct stages during each half cycle of alternating current: a first voltage application from 0 to π/2 radians, and a second voltage application from π/2 to π radians. This periodic action allows the heater to reach the required temperature faster while limiting overall power consumption by controlling when voltage is applied during each cycle.
Solution Approach 2:
The patent applies voltage preliminarily during the first stage (0 to π/2 radians) to start heating the heater before the main heating phase. This preliminary action prepares the heater for the second voltage application, enabling it to reach the target temperature more efficiently while managing power consumption.
2Loss of time
If voltage application timing is optimized to shorten heating time, then First Print Out Time is reduced, but control complexity increases
Solution Approach 1:
The patent uses feedback from a current sensor to detect the actual current flowing through the heater during voltage application. This feedback allows the controller to adjust the voltage application timing and duration dynamically, optimizing heating efficiency while managing control complexity through adaptive control rather than fixed timing.
Solution Approach 2:
The patent changes the parameter of voltage application timing by applying voltage during specific phase angles of the alternating current cycle (0 to π/2 and π/2 to π radians). This parameter optimization allows the system to achieve faster heating while keeping the control logic relatively simple by leveraging the natural AC waveform characteristics.
3Speed
If the heater is energized for longer duration during each half cycle, then temperature reach time is reduced, but the alternating current waveform utilization becomes inefficient
Solution Approach 1:
The patent divides each half cycle into two periodic voltage application stages: the first stage from 0 to π/2 radians and the second stage from π/2 to π radians. This periodic structure ensures that voltage is applied during the most efficient portions of the AC waveform, maximizing temperature reach speed while maintaining high current utilization efficiency by avoiding voltage application during low-current periods.
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 enables the heaters to reach predetermined temperatures faster, thereby reducing FPOT while limiting power supply, and allows for more efficient energization of the auxiliary and main heaters during a half cycle of alternating current.
Implementation Method 1
a current sensor connected in series to the first heater
Implementation Method 2
a first heater, a current sensor connected in series to the first heater
Data Source
AI summary
A heating system includes a heater, a switch providing alternating current to the heater, and a current sensor electrically connected between the switch and the heater. The heating system also includes a controller that controls operation of the switch. The controller activates the switch during a portion of a half cycle of the alternating current having increasing amplitude under a threshold. The controller determines, based on a signal received from the current sensor during the activation of the switch, a time period from the start of the half cycle to a threshold timing at which the alternating current reaches the threshold. The controller reactivates the switch at a timing on or after a timing obtained by subtraction of the determined time period from an end of the half cycle. The heating system is useable within an image forming apparatus.