Cam Mechanism for Developing Roller Positioning
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Solution Overview
Problem
Image-forming apparatuses experience collision sound due to backlash and idle rotation of gears when the developing roller moves from a separated position to a contact position with the photosensitive drum.
Innovation Solution
Incorporating a separation mechanism with an end cam and cam follower that utilizes sloped surfaces to gently guide the developing roller between contact and separated positions, reducing displacement per unit rotation angle and minimizing gear collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gear train is used to transmit driving force to the developing roller, then the developing roller can be moved between contact and separated positions, but meshing engagement between neighboring gears may be reversed due to backlash, resulting in generation of collision sound
Solution Approach 1:
A cam mechanism is introduced as an intermediary between the motor and the developing roller positioning system. The cam converts rotational motion into controlled linear motion, eliminating direct gear-to-gear engagement during the critical positioning phase and thereby preventing collision sounds caused by backlash.
Solution Approach 2:
The patent replaces the traditional gear-based mechanical transmission system with a cam-based mechanism for the specific function of positioning the developing roller. This substitution eliminates the backlash problem inherent in gear systems while maintaining precise control over the roller's movement between contact and separated positions.
2Productivity
If the developing roller is moved quickly from separated position to contact position, then productivity is improved, but collision sound is generated due to gear backlash
Solution Approach 1:
The cam mechanism serves as an intermediary that decouples the motor's rotational speed from the developing roller's linear speed. This allows the motor to rotate at high speed while the cam controls the roller's movement to occur at an optimized speed that prevents collision sounds, thus maintaining productivity without generating harmful noise.
Solution Approach 2:
The cam profile is designed with dynamic characteristics that control the acceleration and deceleration of the developing roller. By optimizing the cam's geometric parameters, the system achieves rapid positioning while avoiding sudden movements that would cause gear backlash and collision sounds, thereby balancing productivity and noise reduction.
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
The solution effectively suppresses the generation of collision sound during the movement of the developing roller, enhancing the operational silence and precision of the image-forming apparatus.
Implementation Method 1
an end cam rotatable in a rotational direction; and a cam follower movable between a first position at which the developing roller is at the separated position and a second position at which the developing roller is at the contact position in accordance with a rotation of the end cam
Data Source
AI summary
An image-forming apparatus includes a motor, a photosensitive drum, a developing roller, and a separation mechanism for moving the developing roller relative to the photosensitive drum. The separation mechanism includes: an end cam rotatable in a rotational direction; and a cam follower movable in accordance with a rotation of the end cam. The end cam includes a first surface, a second surface, a first sloped surface connecting the second surface to the first surface, and a second sloped surface connecting the first surface to the second surface in the rotational direction. The second sloped surface includes: a steep slope surface connected to the second surface; and a gentle slope surface connecting the first surface to the steep slope surface. The gentle slope surface slopes relative to the first surface by an angle smaller than an angle by which the steep slope surface slopes relative to the first surface.