Power Supply Control for Electrophotographic Apparatuses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power supply devices for electrophotographic image forming apparatuses experience delays in rising direct-current voltage due to residual electric charges, leading to insufficient output before switching to constant current control, which can result in prolonged charging periods and reduced image transfer efficiency.
Innovation Solution
A power supply controlling device that includes a direct-current power supply, an alternating-current power supply, a bypass capacitor, and a power supply controlling unit, which controls the direct-current voltage based on target values and stored alternating-current values to quickly rise the direct-current voltage by feeding back the stored current into the bypass capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass capacitor is used to prevent alternating-current output from routing into direct-current power supply, then the power supply device can prevent voltage routing issues, but the direct-current voltage rising period becomes prolonged due to residual electric charges
Solution Approach 1:
The control unit performs preliminary action by detecting residual electric charges in the bypass capacitor before switching from constant voltage control to constant current control. When residual charges are detected, the control unit delays the switching timing, ensuring that constant current control starts only when the capacitor is sufficiently discharged. This preliminary detection and conditional switching prevents the direct-current voltage from dropping due to residual charges, thereby maintaining reliable voltage output while reducing the overall rising period.
Solution Approach 2:
The control unit implements feedback by continuously monitoring the electric charge state of the bypass capacitor. The detection unit provides real-time information about residual charges to the control unit, which then adjusts the switching timing between constant voltage and constant current control modes. This feedback mechanism ensures that the power supply system adapts to the actual capacitor state, preventing voltage instability while optimizing the voltage rising speed.
2Speed
If constant current control is started immediately after constant voltage control, then the direct-current voltage can rise faster, but residual electric charges cause the direct current output to drop below expected levels
Solution Approach 1:
The control unit performs preliminary detection of residual electric charges in the bypass capacitor before initiating the switch to constant current control. This preliminary action allows the system to determine the appropriate switching timing based on the actual charge state, ensuring that constant current control starts when conditions are favorable. This prevents the direct current output from dropping below expected levels while still achieving fast voltage rising by avoiding unnecessary delays.
Solution Approach 2:
The control unit dynamically adjusts the switching timing between constant voltage and constant current control modes based on real-time detection of residual electric charges. Rather than using a fixed switching schedule, the system adapts its control strategy to the actual capacitor state, optimizing both the voltage rising speed and the stability of direct current output. This dynamic adjustment ensures reliable operation across varying conditions.
3Loss of time
If the controlling method switches from constant voltage control to constant current control, then the charging period shortens, but residual electric charges delay the start of constant current control and may cause insufficient direct current output
Solution Approach 1:
The control unit performs preliminary detection of residual electric charges before switching controlling methods. By detecting the charge state in advance, the system can determine the optimal switching timing, ensuring that constant current control starts at the right moment. This preliminary action shortens the charging period by eliminating unnecessary delays while preventing insufficient direct current output that would occur with premature switching.
Solution Approach 2:
The detection unit provides real-time feedback about the bypass capacitor's charge state to the control unit. This feedback enables the control unit to make informed decisions about when to switch from constant voltage to constant current control, optimizing the charging period while ensuring sufficient direct current output for efficient image transfer. The feedback mechanism balances the competing requirements of speed and productivity.
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 direct-current voltage to rise within the expected period, shortening the power-on time and sheet-to-sheet time, enhancing printing productivity and maintaining image quality by preventing undershoots in the direct current output.
Implementation Method 1
a bypass capacitor configured to partially store therein an output from the alternating-current power supply and configured to, when the direct-current voltage is output from the direct-current power supply while no electric charge is stored therein, store therein a second direct current being a part of a first direct current output from the direct-current power supply
Data Source
AI summary
A power supply controlling device includes: a direct-current power supply configured to output a direct-current voltage; an alternating-current power supply configured to output one selected from between a superimposed voltage obtained by superimposing an alternating-current voltage onto the direct-current voltage and the direct-current voltage; a bypass capacitor configured to partially store therein an output from the alternating-current power supply and configured to, when the direct-current voltage is output from the direct-current power supply while no electric charge is stored therein, store therein a second direct current being a part of a first direct current output from the direct-current power supply in conjunction with the output of the direct-current voltage; and a power supply controlling unit configured to cause the direct-current power supply to control a level of the direct-current voltage based on a target value for the first direct current and a value indicating the second direct current.