Process Cartridge Friction Torque Control for Drum Wobble
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Solution Overview
Problem
Existing process cartridges require large driving forces to rotate photosensitive drums and developing rollers due to uneven rotational speeds, leading to issues like 'banding' in image formation, which is exacerbated by high friction resistance components.
Innovation Solution
A process cartridge design incorporating a resistance generating member that creates a resistance torque smaller than the torque causing the photosensitive drum to rotate due to friction with the developing roller, allowing the photosensitive drum to rotate with reduced driving force by following the developing roller's rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If friction resistance components are increased to suppress drum wobble, then rotational stability is improved, but driving force requirement increases
Solution Approach 1:
The patent converts the harmful friction resistance into a beneficial force by designing the friction between the developing roller and photosensitive drum to drive the photosensitive drum rotation. The friction torque TQ2 is made larger than the resistance torque TQ1, so that friction becomes the primary driving mechanism rather than a resistive force to be overcome.
Solution Approach 2:
The system achieves self-driven rotation of the photosensitive drum through the friction interaction with the developing roller. The developing roller's rotation automatically induces photosensitive drum rotation via friction contact, eliminating the need for separate driving mechanisms and reducing overall driving force requirements.
2Speed
If driving force is increased to rotate photosensitive drum and developing roller, then rotational speed is maintained, but image quality deteriorates due to banding
Solution Approach 1:
The patent creates a feedback mechanism where the friction between the developing roller and photosensitive drum continuously adjusts the photosensitive drum's rotational speed to match the developing roller's speed. This automatic speed synchronization prevents the rotational unevenness that causes banding, maintaining both speed and image quality.
Solution Approach 2:
Friction acts as an intermediary mechanism that transfers rotational motion from the developing roller to the photosensitive drum. This intermediary friction force smoothly couples the two components, enabling synchronized rotation without direct mechanical engagement that could cause speed variations and banding.
3Stability of the object's composition
If resistance torque TQ1 is increased to prevent photosensitive drum slippage, then rotational control is improved, but driving force requirement increases
Solution Approach 1:
The patent optimizes the parameter relationship between resistance torque TQ1 and friction torque TQ2, specifically setting TQ1 < TQ2. This parameter change transforms the resistance torque from a dominant force requiring large driving power into a subordinate force that works in conjunction with friction to achieve controlled rotation with minimal driving force.
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 configuration reduces the driving force required for both the photosensitive drum and developing roller, minimizing rotation unevenness and preventing 'banding' in image formation, with a torque difference of TQ1-TQ2 ≤ -2 Ncm effectively suppressing drum wobble.
Implementation Method 1
the resistance generating member is configured to generate a resistance torque TQ1 serving as resistance between the frame and photosensitive drum
Implementation Method 2
A surface of the developing roller contacts a surface of the photosensitive drum through toner. In a case where the developing roller rotates according to the driving force, the resistance torque TQ1 is smaller than a torque TQ2 that causes the photosensitive drum to rotate due to friction between the surface of the developing roller and the surface of the photosensitive drum
Data Source
AI summary
A photosensitive drum is rotatable about a first axis extending in a particular direction. A frame rotatably supports the photosensitive drum. A developing roller is rotatable according to driving force about a second axis extending in the particular direction. A surface of the developing roller contacts a surface of the photosensitive drum through toner. A resistance generating member generates a resistance torque TQ1 serving as resistance between the frame and photosensitive drum in a case where the photosensitive drum rotates relative to the frame. In a case where the developing roller rotates according to the driving force in a state where the surface of the developing roller contacts the surface of the photosensitive drum through toner, the resistance torque TQ1 is smaller than a torque TQ2 that causes the photosensitive drum to rotate due to friction between the surface of the developing roller and the surface of the photosensitive drum.