Image Forming Apparatus Recovery Current Control
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Solution Overview
Problem
Existing electro-photographic image forming apparatuses face issues with excessive current flow to the cleaning roller, leading to increased size of the high-voltage power circuit and the image forming apparatus, due to the electrification of the photosensitive drum.
Innovation Solution
An image forming apparatus with a control unit that determines if the recovery current exceeds a predetermined value, and if so, increases the transfer current to prevent excessive current flow, thereby reducing the surface potential of the image carrier and preventing inflow current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning roller is applied with a higher voltage to recover residual developing agent, then the recovery effectiveness is improved, but the current flow from the electrified photosensitive drum to the cleaning roller increases, requiring a larger high-voltage power circuit and increasing the apparatus size
Solution Approach 1:
The transfer unit performs preliminary action by transferring the developing agent image to the recording medium before the recovery unit operates. By optimizing the transfer current and transfer voltage applied to the transfer unit, the surface potential of the photosensitive drum is reduced in advance, which prevents excessive current flow to the cleaning roller during the subsequent recovery operation, thereby avoiding the need for a larger high-voltage power circuit
Solution Approach 2:
The invention changes the electrical parameters (current and voltage) applied to the transfer unit dynamically. By controlling the transfer current and transfer voltage to specific ranges, the surface potential of the photosensitive drum is adjusted to an optimal level that enables effective recovery operation without causing excessive current flow to the cleaning roller
2Reliability
If the transfer current is increased to reduce surface potential of the image carrier, then the recovery current is reduced, but the energy consumption and heat generation during transfer operation increases
Solution Approach 1:
The invention applies partial action by controlling the transfer current and transfer voltage to specific ranges that are sufficient to reduce the surface potential of the photosensitive drum to an appropriate level for recovery operation, without applying excessive current that would cause unnecessary energy consumption and heat generation. The transfer current is controlled to be in a range that achieves the desired effect with minimal energy waste
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 prevents excessive current flow to the cleaning roller and the high-voltage power circuit, maintaining the apparatus size and ensuring efficient image formation by controlling the transfer current.
Implementation Method 1
a transfer unit configured to transfer the developing agent image held on the image carrier to a recording medium
Implementation Method 2
a recovery unit configured to recover the developing agent remaining on the image carrier
Data Source
AI summary
An image forming apparatus comprises an image carrier configured to hold a developing agent image; a transfer unit that transfers the developing agent image to a recording medium; a first application unit that controls a transfer voltage applied to the transfer unit; a recovery unit that recovers the developing agent remaining on the image carrier; a second application unit that controls a recovery voltage applied to the recovery unit; a determination unit that determines whether or not a recovery current flowing between the image carrier and the recovery unit exceeds a first predetermined current value; and a control unit that, when the determination unit makes a positive determination that the recovery current has exceeded the first predetermined current value, performs a protective control for controlling the first application unit such that a transfer current flowing between the image carrier and the transfer unit becomes greater.