Exposure Unit Reflector Geometry for Laser Alignment
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Solution Overview
Problem
The existing image formation devices face challenges in maintaining the precise alignment of the exposure unit after replacement, leading to deviations in the laser beam path and non-uniform electrostatic latent images, which affects the quality of the formed images.
Innovation Solution
The exposure unit is designed with a specific arrangement of reflectors where the distance from the end reflector to the photoconductor drum is less than the separation distances between reflectors, ensuring accurate beam alignment and uniform image formation despite potential offsets during reinstallation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the exposure unit is detachably mounted on the upper cover part to enable easy replacement, then the ease of operation is improved, but the manufacturing precision deteriorates due to position offset after reinstallation
Solution Approach 1:
A positioning plate is introduced as an intermediary component between the exposure unit and the upper cover part. The positioning plate includes a positioning protrusion that fits into a positioning groove, serving as a mediator to ensure accurate positioning and prevent offset during reinstallation, thereby resolving the contradiction between ease of replacement and alignment precision
Solution Approach 2:
The invention changes the dimensional parameters of the positioning structures by specifying that the distance from the end reflector to the photoconductor drum surface is less than the separation distance between adjacent reflectors. This parameter configuration ensures that even with minor positioning variations, the laser beam remains within the acceptable optical path tolerance, maintaining image quality while allowing easy replacement
2Ease of operation
If installation clearance is provided between the exposure unit and upper cover part to allow easy demounting, then the ease of operation is improved, but the reliability deteriorates due to laser beam deviation from optical path
Solution Approach 1:
The positioning plate acts as a mediator that decouples the installation clearance requirement from the optical path accuracy requirement. It allows the exposure unit to be easily mounted and demounted while maintaining precise optical alignment through the positioning protrusion-groove mechanism
Solution Approach 2:
The positioning structures (protrusion and groove) are pre-configured during manufacturing to establish the correct optical path geometry before the exposure unit is installed. This preliminary action ensures that when the exposure unit is reinstalled, the laser beam automatically follows the predetermined optical path without deviation
3Manufacturing precision
If the exposure unit position is fixed securely to maintain optical path accuracy, then the manufacturing precision is improved, but the ease of operation deteriorates due to difficulty in replacement
Solution Approach 1:
The mounting system is segmented into separate components: the upper cover part, the positioning plate, and the exposure unit. This segmentation allows the exposure unit to be easily detached and replaced while the positioning plate remains fixed on the upper cover part, maintaining optical precision without compromising replaceability
Solution Approach 2:
The positioning plate serves as a fixed intermediary on the upper cover part that provides stable positioning features. This allows the exposure unit to be securely positioned during operation while enabling easy removal and reinstallation, resolving the contradiction between secure fixation and ease of replacement
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 arrangement ensures that the focused beam consistently reaches the predetermined position on the photoconductor drum, improving the uniformity and quality of the electrostatic latent image, thereby maintaining image quality even after reinstallation of the exposure unit.
Implementation Method 1
a laser beam emitter for emitting a laser beam corresponding to the exposure signal
Implementation Method 2
plural reflectors which are sequentially disposed on a predetermined optical path for receiving the focused beam and reflecting the focused beam plural times
Data Source
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AI summary
Disclosed is an exposer unit comprising a laser beam emitter for emitting a laser beam corresponding to an exposure signal; a rotation polygon mirror part including a rotation polygon mirror for receiving and deviating the laser beam; an f-theta lens for receiving the deviated laser beam and generating a focused beam for emission; and plural reflectors disposed on a predetermined optical path whose start point is the f-theta lens and whose end point is a surface of a photoconductor drum in an image formation unit, and sequentially arranged according to predetermined separation distances for receiving the focused beam and reflecting the focused beam plural times along the predetermined optical path so as to cause the focused beam to arrive at the surface of the photoconductor drum. The plural reflectors include a forefront reflector and an end reflector, the forefront reflector being used for receiving the focused beam, the end reflector being used for reflecting the focused beam to the surface of the photoconductor drum. The distance from the end reflector to the surface of the photoconductor drum is less than both the predetermined separation distances and the distance from the forefront reflector to the rotation polygon mirror.