Resin Supporting Frame for Exposure Unit in Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses face issues with interference between exposure unit positioning portions and housing positioning portions during cover movement, and the size increase due to metal plate springs requiring grounding members.
Innovation Solution
The design incorporates a rotatable cover with a recessed first engaging part and a holding member with a regulation part, allowing the exposure unit to rock and move in the auxiliary scanning direction, and uses a resin-made supporting frame with an elastic member to eliminate the need for conductive grounding, thus preventing interference and downsizing the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the protrusion is inserted in the hole to prevent relative movement between the exposure unit and the holding member, then the exposure unit is fixed in position, but the unit-side positioning portion and the housing-side positioning portion interfere with each other when the cover is being moved
Solution Approach 1:
The patent applies the dynamics principle by making the engagement between the protrusion and hole conditional rather than continuous. The engagement occurs only when the cover is in a specific position (closed position), allowing the exposure unit to be fixed during operation. When the cover is opened or being moved, the engagement disengages, permitting the positioning portions to move without interference. This dynamic engagement resolves the contradiction by providing position stability only when needed while preventing interference during cover movement.
2Strength
If the plate spring is made of metal to provide mechanical support, then the LED holder gains structural strength, but a conducting member for grounding is required, increasing the device size
Solution Approach 1:
The patent applies the parameter changes principle by changing the material parameter of the plate spring from metal to resin. This material substitution maintains the mechanical support function while eliminating the electrical conductivity requirement. Since resin is non-conductive, the grounding member becomes unnecessary, allowing the LED holder to be downsized. This resolves the contradiction by achieving structural strength through resin material properties rather than metal conductivity.
Solution Approach 2:
The patent applies the mechanics substitution principle by replacing the metal plate spring (which provided both mechanical support and electrical grounding) with a resin plate spring (which provides only mechanical support). This substitution eliminates the need for a separate grounding mechanism, reducing the overall device size while maintaining the necessary structural strength for LED holder support.
3Stability of the object's composition
If the exposure unit is fixed to the holding member to prevent movement, then positioning is stable, but the cover cannot be opened or closed without causing interference
Solution Approach 1:
The patent applies the dynamics principle by creating a conditional engagement system where the protrusion-hole connection is active only during specific operations. When the cover is closed, the engagement provides position stability. When the cover is opened or being moved, the engagement automatically disengages, allowing free movement of the positioning portions without interference. This dynamic on/off engagement resolves the contradiction between maintaining stability and enabling operation.
Solution Approach 2:
The patent applies the preliminary action principle by designing the engagement mechanism to automatically disengage before interference can occur. As the cover begins to open or move, the protrusion is pulled out of the hole in advance, preventing any potential interference between positioning portions. This preliminary disengagement ensures smooth cover operation while maintaining stability during the closed state.
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 prevents interference between positioning portions and reduces the device's size by eliminating the need for grounding members, enhancing the operational stability and compactness of the image forming apparatus.
Implementation Method 1
an LED holder which supports the LED head via a plate spring
Implementation Method 2
a resin-made supporting frame with an elastic member to eliminate the need for conductive grounding
Data Source
AI summary
An image forming apparatus includes a photoconductive member and an exposure unit. The exposure unit has a supporting frame made of resin, a holding case attached to the supporting frame, a plurality of emitting elements and a lens array held by the holding case, and a grounded metal wire. The holding case is made of resin and elongated in a longitudinal direction. The photoconductive member is configured to be exposed to light emitted by the plurality of light emitting elements and converged by the lens array. The supporting flame holds the metal wire such that the metal wire extends in the longitudinal direction and faces the holding case.