Process Cartridge Light Guide Positioning for Shutter Interference
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face challenges in efficiently exposing photosensitive drums due to interference between the pre-exposure member and the shutter member, leading to increased costs from higher light source intensity requirements to ensure adequate exposure.
Innovation Solution
A process cartridge design where the light guide member is positioned downstream of the transfer position and upstream of the charging position, with a shutter portion that moves between closed and open positions, and a connecting portion at each end to facilitate movement relative to the cartridge body, allowing the incident portion of the pre-exposure member to be outside the shutter member's rotation locus, thus avoiding interference and reducing the need for increased light source intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pre-exposure member is disposed upstream of the charging means to make the surface potential constant, then the photosensitive drum surface potential is stabilized, but the incident portion of the pre-exposure member interferes with the rotation locus of the shutter member, requiring increased light source intensity
Solution Approach 1:
The patent repositions the incident portion of the pre-exposure member from the radial direction (inside the shutter rotation locus) to the axial direction (outside the shutter rotation locus). This dimensional change allows the light to enter the photosensitive drum from the end surface rather than from the side, eliminating interference with the shutter member's rotation while maintaining pre-exposure functionality
Solution Approach 2:
The patent introduces a light guide member as an intermediary component that channels light from the light source to the photosensitive drum surface. The light guide member includes an incident portion positioned outside the shutter rotation locus, allowing light to be guided around the shutter member's path without direct interference, thus reducing the required light source intensity
2Reliability
If the light source intensity is increased to ensure adequate exposure, then the exposure reliability is improved, but the cost and energy consumption increase
Solution Approach 1:
The patent replaces the conventional radial light entry mechanism with an axial light entry mechanism through the light guide member. This substitution changes the optical path from requiring high-intensity light sources to allow efficient light guidance with lower intensity, as the light travels through the light guide member rather than directly illuminating from the side
Solution Approach 2:
The patent changes the spatial parameters of the light entry system by positioning the incident portion axially outside the shutter rotation locus. This parameter change optimizes the optical path length and light distribution, allowing adequate exposure with reduced light source intensity and lower energy consumption
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 design effectively suppresses the increase in light source intensity requirements, reducing costs while ensuring reliable exposure of the photosensitive drum, thereby improving the operational efficiency and cost-effectiveness of the image forming process.
Implementation Method 1
a light guide member for irradiating a surface of the photosensitive drum with light
Data Source
AI summary
A process cartridge includes a photosensitive drum; a light guide member; a shutter portion movable between a closed position where the shutter portion covers the surface of the drum and an open position where the surface of the drum is exposed; and a connecting portion, provided at each of end portions of the shutter portion with respect to an axial direction of the drum, for connecting the shutter portion so as to be movable relative to a main body portion of the process cartridge. The light guide member includes an incident portion, at one end portion thereof with respect to the axial direction of the drum, for irradiating the surface of the drum with light incident on the incident portion. The incident portion is positioned outside the connecting portion with respect to the axial direction of said photosensitive drum.