Integrated Cover-Plate Scanning Unit for Compact Laser Printers
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Solution Overview
Problem
The miniaturization of electrophotographic image forming apparatuses, such as laser printers, is hindered by the need for a rigid-body plate between the scanning unit and the photosensitive member, which limits the reduction of the distance and height of the apparatus.
Innovation Solution
The design incorporates a scanning unit with a unit frame, light-emitting section, deflector, first and second reflection optical elements, and a rigid-body plate that functions as both a structural support and cover, allowing the scanning unit to be suspended below the plate, eliminating the need for a separate rigid-body plate between the scanning unit and the photosensitive member, and utilizing screw-hole pedestals for precise fastening to prevent warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid-body plate is disposed across the process unit to support the scanning unit, then structural stability is improved, but the distance between the scanning unit and the photosensitive member cannot be shortened
Solution Approach 1:
The patent combines the cover structure and the rigid-body support plate into a single integrated component. The cover is configured to extend across the process unit and simultaneously serve as the rigid-body plate, eliminating the need for a separate support structure. This merging allows the scanning unit to be positioned closer to the photosensitive member while maintaining structural stability through the integrated cover-plate assembly.
2Strength
If the rigid-body plate is placed inside the image forming apparatus to support the scanning unit, then mechanical support is improved, but the apparatus height cannot be reduced
Solution Approach 1:
The cover is designed to perform multiple functions simultaneously: it serves as the housing cover for the image forming apparatus, provides the rigid-body support plate for the scanning unit, and contributes to the overall structural framework. This multi-functionality eliminates the need for additional internal support structures that would increase apparatus height, achieving both mechanical strength and compact dimensions.
3Volume of moving object
If the scanning unit is positioned close to the photosensitive member for miniaturization, then apparatus compactness is improved, but optical path length may be insufficient
Solution Approach 1:
The patent employs reflective optics (mirrors) to redirect the optical path in alternative directions rather than using a straight-line path. By utilizing vertical and lateral reflections, the optical beam can traverse a sufficiently long path length while the physical distance between the scanning unit and photosensitive member remains short, enabling both compactness and adequate optical path length.
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 enables the miniaturization of the image forming apparatus by shortening the distance between the scanning unit and the photosensitive member, reducing the apparatus's height, and improving its compactness while maintaining sufficient optical path length, thus enhancing the miniaturization and cost-effectiveness.
Implementation Method 1
a first reflection optical element for reflecting the light beam, which has been deflected by the deflector and travels toward the outer peripheral wall, toward a position below the base section through the opening
Implementation Method 2
a second reflection optical element that is disposed at the position below the base section and guides the reflected light beam toward the photosensitive member
Data Source
AI summary
In an image forming apparatus, a rigid-body plate, which is to be placed across a scanning unit for constituting a housing, also serves as an upper cover of the scanning unit, and the scanning unit is suspended on the rigid-body plate at an interior position from a top cover of an upper portion of the housing of the image forming apparatus. This obviates a necessity for interposing, between the scanning unit and a photosensitive drum, a rigid-body plate or the like used for mounting the scanning unit, thereby shortening a distance between the scanning unit and the photosensitive drum.