Charge Roll Separation Cover for Image Carrier Unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional charge devices in electrophotographic image forming apparatuses, such as those using corona discharge, generate harmful ozone and nitrogen oxide, while contact charging methods can cause permanent distortion and image defects due to prolonged contact and vibration.
Innovation Solution
An image carrier unit with a charge roll and a separation cover that can be latched to detach the charge roll from the photoreceptor drum, preventing prolonged contact and reducing the risk of distortion and image defects, and incorporating a packaging material to protect the components during storage and transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If contact charging is used with a charge roll pressed against the photoreceptor, then power efficiency is improved and ozone generation is reduced, but permanent distortion occurs in the charge roll contact portion causing image defects
Solution Approach 1:
The patent makes the charge roll movable rather than fixed, allowing it to be dynamically adjusted between contact and separation states. The charge roll can be pressed against the photoreceptor during charging operations and separated when not in use, preventing permanent distortion while maintaining power efficiency during active charging.
Solution Approach 2:
The patent implements periodic contact and separation of the charge roll with the photoreceptor. The charge roll is pressed against the photoreceptor only during required charging operations and separated during storage or transport, avoiding continuous contact that causes distortion while ensuring charging functionality when needed.
2Reliability
If the charge roll is pressed against the photoreceptor over a long period, then charging function is maintained, but the charge roll and photoreceptor rub against each other during vibration and transport causing image quality defects
Solution Approach 1:
The patent implements a movable charge roll mechanism that can be dynamically positioned in contact or separated state. During transport or storage, the charge roll is separated from the photoreceptor to eliminate friction damage from vibration, while maintaining charging function when the unit is in operational position.
Solution Approach 2:
The patent separates the charge roll from the photoreceptor drum as independent movable components rather than fixed integrated parts. This segmentation allows the charge roll to be positioned independently - separated during transport to prevent friction damage, and brought into contact during operation to maintain charging function.
3Reliability
If a separation cover is provided to detach the charge roll from the photoreceptor drum, then permanent distortion and image defects are prevented, but device complexity increases
Solution Approach 1:
The separation cover serves multiple functions: it protects the charge roll and photoreceptor during transport, maintains separation to prevent distortion, and can be easily opened during operation. This multi-functionality justifies the added structural element by providing both protective and operational benefits.
Solution Approach 2:
The separation cover is pre-provided in the structure to enable preliminary separation of the charge roll from the photoreceptor drum before transport or storage operations begin. This preliminary protective action prevents distortion from occurring in the first place, rather than requiring complex corrective mechanisms later.
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
Prevents permanent distortion and image defects by ensuring the charge roll is separated from the photoreceptor drum, reducing the occurrence of density unevenness and white stripes, and protecting the components from environmental factors like humidity and light-induced fatigue.
Implementation Method 1
a spring that causes the charge roll to be pressed against the photoreceptor drum with constant pressure
Implementation Method 2
a hook portion disposed on the cover portion, that is inserted between the charge roll and the photoreceptor drum and is hooked onto the charge roll when the cover portion is rotated toward the charge roll so as to cause the charge roll to separate from the photoreceptor drum
Implementation Method 3
contact charging, where a conductive charge roll is brought into direct contact with a photoreceptor to charge the photoreceptor
Data Source
AI summary
An image carrier unit that is removably loaded into a main body of an image forming apparatus includes: an image carrier on which an image is formed; a charge roll that charges the image carrier; a biasing member that causes the charge roll to be pressed against the image carrier; and a separation cover provided with a cover portion that covers the charge roll by a latching portion thereof being caused to latch into a body frame of the image carrier unit and the cover portion being rotated toward the charge roll, and a hook portion disposed on the cover portion, that is inserted between the charge roll and the image carrier and is hooked onto the charge roll when the cover portion is rotated toward the charge roll so as to cause the charge roll to separate from the image carrier.