Toner Interposition Control for Electrophotographic Drum Protection
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the migration of constituents from the intermediate transfer belt to the photosensitive drum can lead to image defects like streaks due to prolonged contact, and excessive toner interposed between the image bearing member and the rotating member complicates cleaning processes.
Innovation Solution
The apparatus includes a control unit that manages the application of DC and AC voltages to the charging and developing devices, allowing for precise control of toner adhesion and positioning at the end of an image forming job, ensuring minimal toner is left between the image bearing member and the rotating member, thereby preventing migration and simplifying cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If toner is interposed between the photosensitive drum and intermediate transfer belt to prevent constituent migration, then image quality is improved, but excessive toner requires more cleaning time
Solution Approach 1:
The invention changes the electrical parameters (voltage and timing) of the charging device to precisely control toner adhesion. By adjusting the charging voltage to a specific range and controlling the timing of voltage application, the system achieves minimal sufficient toner interposition that prevents constituent migration while requiring minimal cleaning time.
Solution Approach 2:
The invention applies partial action by using just enough toner interposition to prevent constituent migration rather than excessive toner. The controlled charging voltage ensures that only the minimum necessary toner adheres to the photosensitive drum surface, avoiding the need for extensive cleaning while still achieving the protective effect.
2Loss of energy
If the photosensitive drum and intermediate transfer belt stop in contact for prolonged period, then energy consumption is reduced, but constituents migrate causing image defects
Solution Approach 1:
The invention performs preliminary action by interposing toner between the photosensitive drum and intermediate transfer belt before they stop in contact. This preventive measure ensures that when the components stop in contact for prolonged periods, the toner layer already in place prevents constituent migration, allowing energy-saving operation without image quality degradation.
Solution Approach 2:
The invention introduces toner as an intermediary substance between the photosensitive drum and intermediate transfer belt. This intermediary layer prevents direct contact between the components, blocking the migration path of constituents while allowing the components to remain in contact for extended periods without causing image defects.
3Manufacturing precision
If DC voltage is applied longer to ensure complete image formation, then image completeness is improved, but toner adhesion control becomes difficult
Solution Approach 1:
The invention applies dynamic control by adjusting the charging voltage based on the operational state. The charging voltage is set to a specific range during the image formation process to ensure complete image formation, and then adjusted to a different range after image formation to control toner adhesion for the interposition phase, optimizing both image completeness and toner control.
Solution Approach 2:
The invention uses periodic action by applying charging voltage in distinct phases: first applying DC voltage for a predetermined period to ensure complete image formation, then switching to a different voltage regime to control toner adhesion. This periodic switching of voltage conditions achieves both complete imaging and controlled toner interposition.
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 approach effectively prevents image defects by minimizing toner migration and streamlines the cleaning process, ensuring consistent image quality and reducing the time required for toner removal.
Implementation Method 1
a charging device configured to charge a surface of the image bearing member
Implementation Method 2
an exposing device configured to expose the charged surface of the image bearing member and form an electrostatic latent image
Implementation Method 3
a developing device configured to develop the electrostatic latent image formed on the surface of the image bearing member by voltage being applied where AC voltage has been superimposed on DC voltage
Implementation Method 4
the control unit drives the image bearing member in a state with AC voltage applied to the developing device so as to adhere toner to the image bearing member
Data Source
AI summary
When ending image forming, a state is realized where charging by a charging roller is stopped (charging bias off) and also applying DC voltage at a developing device is stopped (developing bias DC off). In this state, AC voltage is applied to the developing device (developing bias AC on), thereby adhering toner to the surface of a photosensitive drum and forming interposing toner. Driving of the photosensitive drum and an intermediate transfer belt is then stopped in the state with the interposing toner interposed between the photosensitive drum and intermediate transfer belt.