Piezoelectric Transformer Power Supply Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional high-voltage power supply apparatus using piezoelectric transformers in image forming apparatuses face challenges in stable voltage control, often resulting in circuit oscillations that degrade printing quality.
Innovation Solution
A power supply unit incorporating a piezoelectric transformer, an output voltage detecting circuit, a comparator, and a driving frequency supplying circuit, where the time constant of the output voltage setting signal is longer than that of the output voltage detecting circuit, allowing for stable voltage control by adjusting the driving frequency based on the comparison between the setting and detecting signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a piezoelectric transformer is used to generate high voltage, then the apparatus becomes compact and lightweight, but the output voltage cannot be controlled and circuit oscillation occurs
Solution Approach 1:
The patent implements a feedback control system where the output voltage of the piezoelectric transformer is detected and fed back to adjust the driving frequency. The driving frequency supplying circuit modifies the frequency based on the detected output voltage to maintain stable operation and prevent oscillation, resolving the control instability issue while retaining the compact piezoelectric transformer design
Solution Approach 2:
The patent changes the driving frequency parameter of the piezoelectric transformer based on the detected output voltage. By dynamically adjusting the driving frequency in response to voltage variations, the system achieves stable voltage control without oscillation, maintaining the advantages of the piezoelectric transformer while eliminating its main drawback
2Reliability
If electromagnetic transformer is used to generate high voltage, then voltage control is achievable, but the apparatus becomes large and heavy
Solution Approach 1:
The patent replaces the electromagnetic transformer (which relies on magnetic field and mechanical coupling) with a piezoelectric transformer (which uses piezoelectric effect and electrical field). This substitution dramatically reduces the size and weight of the power supply apparatus while maintaining voltage control capability through the added feedback control mechanism
3Speed
If the time constant of output voltage setting signal is shorter than that of output voltage detecting circuit, then response speed is improved, but circuit oscillation occurs
Solution Approach 1:
The patent optimizes the time constant parameter of the output voltage setting signal to be longer than that of the detecting circuit. This parameter adjustment prevents oscillation by ensuring proper phase relationship in the feedback loop, while still maintaining adequate response speed for practical voltage control applications
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 configuration ensures stable voltage control, preventing circuit oscillations and maintaining high printing quality by effectively managing the output voltage of the piezoelectric transformer.
Implementation Method 1
it is proposed to generate a high voltage by using a flat, light-weight, high-output piezoelectric transformer
Data Source
AI summary
A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, an output voltage control circuit which controls an output voltage from the piezoelectric transformer, and includes a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal. The power supply unit also includes a driving frequency supplying circuit which generates a driving frequency signal of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the driving frequency signal to the piezoelectric transformer. The time constant of the output voltage control circuit is longer than the time constant of the output voltage detecting circuit.