Transfer Voltage Control in Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses using a common voltage unit for both charging and transfer members, changing the voltage output to the charging member during active transfer voltage control (ATVC) leads to fluctuations in detected electric current, making it difficult to set the transfer voltage accurately, which can result in transfer failure and elongates the first print out time (FPOT).
Innovation Solution
The apparatus includes a first voltage unit for outputting a predetermined polarity to both the charging and transfer members, a second voltage unit for outputting an opposite polarity, and a control unit that regulates the transfer voltage by superimposing voltages and temporarily ignoring changes in detected current when the first voltage unit's output changes, ensuring stable transfer voltage setting without reflecting detection results during a predetermined time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage output to the charging member is changed during ATVC execution, then the charging performance is improved, but the detected electric current fluctuates making transfer voltage setting difficult
Solution Approach 1:
The patent segments the voltage control into two independent units: a first voltage unit for the charging member and a second voltage unit for the transfer member. This segmentation allows the charging voltage to be adjusted independently without affecting transfer voltage stability, resolving the contradiction between improved charging performance and maintained current detection accuracy.
Solution Approach 2:
The patent introduces a control unit as an intermediary that manages the relationship between the first and second voltage units. The control unit detects voltage changes from the first voltage unit and compensates by adjusting the second voltage unit accordingly, maintaining stable transfer voltage settings even when charging voltage changes occur.
2Reliability
If the ATVC is re-executed after voltage change to the charging member, then transfer failure is suppressed, but the first print out time is elongated
Solution Approach 1:
The patent performs preliminary voltage setting for the transfer member through the second voltage unit before actual transfer operations begin. By pre-configuring the transfer voltage based on anticipated charging voltage changes, the system avoids the need for time-consuming re-execution of ATVC after voltage changes, thus suppressing transfer failure while minimizing FPOT.
Solution Approach 2:
The patent maintains continuous voltage control by having the second voltage unit continuously adjust transfer voltage in response to first voltage unit changes. This continuous adjustment eliminates interruptions and re-execution delays, keeping the useful action of voltage regulation ongoing without breaking the process flow.
3Device complexity
If a common voltage unit is used for both charging and transfer members, then device complexity is reduced, but voltage control stability deteriorates
Solution Approach 1:
The patent divides the common voltage unit into two separate voltage units: a first voltage unit dedicated to the charging member and a second voltage unit dedicated to the transfer member. This segmentation provides independent control channels for each function, ensuring that voltage changes for charging do not directly affect transfer voltage stability, thus resolving the contradiction between simplified configuration and stable voltage control.
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 effectively suppresses transfer failure while minimizing the FPOT by maintaining stable transfer voltage settings, even when the voltage output to the charging member is changed, thus improving the reliability and efficiency of the image forming process.
Implementation Method 1
a first voltage unit configured to output a voltage having a predetermined polarity to the charging member and the transfer member
Implementation Method 2
a second voltage unit configured to be electrically connected to the first voltage unit and to output a voltage having an opposite polarity to that of the predetermined polarity output to the transfer member
Implementation Method 3
a detection unit configured to detect an electric current flowing through the transfer member
Implementation Method 4
a transfer member configured to form a transfer portion by abutting on the photosensitive member and to transfer the toner image borne by the photosensitive member to a transfer material at the transfer portion
Data Source
AI summary
A control unit can execute regulation control referred to as active transfer voltage control (ATVC) for setting a transfer voltage output from a second voltage unit to a transfer member so as to transfer a toner image from a photosensitive member to a transfer material based on an electric current value detected by a detection unit and a voltage value output from a voltage output unit. When changing a voltage value output from the voltage output unit during execution of the ATVC, the control unit interrupts execution of a predetermined operation of the ATVC in a predetermined time period including a point of time including when the voltage output from the voltage output unit is changed.