Drive Coupling Engagement Timing for Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses using electrophotographic methods, the transition from a disconnected to a connected state of couplings can cause the photosensitive drum or intermediate transfer belt to remain stationary, leading to potential damage and image quality issues due to improper synchronization of motor activation and surface speed.
Innovation Solution
The apparatus includes a drive coupling that moves to an engagement position after motor activation, allowing the transmission of driving force to the driven coupling, and a control unit that applies voltage to the transfer or charging member only after the couplings are securely engaged, preventing electrostatic attraction and ensuring proper rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor is started when the couplings are in the process of connecting (transitioning from disconnected to connected state), then the image forming speed is improved, but the photosensitive drum or belt surface may be damaged due to zero surface speed
Solution Approach 1:
The control unit delays the application of voltage to the transfer member until after the drive coupling has moved to the engagement position and the driving force has been transmitted to the driven coupling. This preliminary sequencing ensures the belt is already rotating at the appropriate speed before the transfer process begins, preventing surface damage while maintaining efficient image forming operation.
2Productivity
If the voltage is applied to the transfer member before the couplings are fully engaged, then the image forming process starts earlier, but electrostatic attraction may cause defective images
Solution Approach 1:
The control unit monitors the position of the drive coupling and uses this feedback information to determine the appropriate timing for applying voltage to the transfer member. By detecting when the coupling has reached the engagement position, the control system ensures voltage application occurs at the optimal moment, preventing electrostatic attraction issues while maintaining high throughput.
3Ease of repair
If the couplings are designed to be removable for maintenance, then the ease of repair is improved, but the complexity of ensuring proper connection and synchronization increases
Solution Approach 1:
The drive coupling is designed with automatic engagement features that allow it to self-align and connect with the driven coupling when the process cartridge is installed. The motor-driven movement of the drive coupling ensures proper engagement without requiring manual intervention, simplifying the repair process while maintaining reliable synchronization through the motor's controlled motion.
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 defective images and reduces the risk of damage to the photosensitive drum or belt by ensuring secure coupling and synchronized rotation, thereby enhancing image forming throughput and quality.
Implementation Method 1
preventing electrostatic attraction and ensuring proper rotation
Implementation Method 2
a drive coupling configured to rotate by a driving force generated by the motor
Implementation Method 3
a belt configured to contact the photosensitive member
Data Source
AI summary
An image forming apparatus for forming image on a recording medium includes a photosensitive member, a motor, a belt, and a drive member to rotate the belt, the drive member including a driven coupling. The apparatus also includes a drive coupling to rotate by a driving force generated by the motor, the drive coupling being movable in an axial direction to take an engagement position at which the driving force is transmittable to the driven coupling, and a release position. The apparatus further includes a transfer member to transfer a toner image onto the recording medium or the belt, a voltage application unit to apply a voltage to the transfer member, and a control unit to cause the voltage application unit to apply the voltage to the transfer member after the drive coupling moves to the engagement position and the driving force is transmitted to the driven coupling.