Image Reading Apparatus Rack Pinion Wobble Suppression
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Solution Overview
Problem
Existing image reading apparatuses using rack and pinion mechanisms experience wobbling issues due to reactive forces, leading to image quality degradation and increased component counts in suppression techniques, and may cause the moving unit to straddle the guide.
Innovation Solution
The image reading apparatus incorporates a sliding structure with a rack disposed between the pinion gear and guide, featuring inclined first slide contact surfaces to displace the moving unit toward the rack and flat second slide contact surfaces to prevent displacement, maintaining stability without increasing the number of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a compression coil spring is used to bias the carriage against the guide member to suppress wobbling, then wobbling is suppressed, but the number of components increases
Solution Approach 1:
The patent combines the guide member with the biasing function by integrating the inclined surface directly into the guide member structure. The guide member simultaneously provides guidance and applies biasing force through its inclined surface geometry, eliminating the need for a separate compression coil spring component while maintaining wobbling suppression functionality.
Solution Approach 2:
The patent changes the geometric parameters of the guide member by incorporating an inclined surface with a specific angle (α). This parameter change allows the guide member to convert the pinion gear's reactive force into a useful biasing force that suppresses wobbling, replacing the need for additional biasing components.
2Stability of the object's composition
If two slide surfaces form inclined surfaces to suppress wobbling, then wobbling is suppressed, but the moving unit may straddle the guide member due to reactive force
Solution Approach 1:
The patent applies different surface characteristics to different regions of the guide member. The first slide surface has an inclined geometry to suppress wobbling, while the second slide surface has a flat geometry to prevent straddling. This local differentiation of surface properties allows the system to achieve both wobbling suppression and positioning accuracy simultaneously.
Solution Approach 2:
The patent divides the slide contact interface into two distinct segments: a first slide surface for wobbling suppression and a second slide surface for positioning stability. This segmentation allows each surface to perform its specific function independently, preventing the moving unit from straddling the guide member while still suppressing wobbling.
3Stability of the object's composition
If the rack is disposed between the pinion gear and guide, then the moving unit moves more stably, but the structural design becomes more complex
Solution Approach 1:
The patent merges the guide member and rack into a single integrated component. The guide member extends in the scanning direction and functions as both a guide and a rack, eliminating the need for a separate rack component while maintaining movement stability through the inclined surface geometry.
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 stabilizes the moving unit's movement, reduces the sliding load, and prevents the moving unit from straddling the guide, enhancing image quality while minimizing component count.
Implementation Method 1
the first slide contact portion includes a first surface with one of the guide and the moving unit, the first surface being inclined so as to displace the moving unit toward the rack
Implementation Method 2
a slide contact portion between the guide and the moving unit
Data Source
AI summary
An image reading apparatus comprises a moving unit on which a reading unit is mounted and which slides on a guide, and a driving unit mounted on the moving unit and includes a pinion gear meshing with a rack which extends in a scanning direction and is disposed between the pinion gear and the guide. A slide contact portion between the guide and the moving unit includes a first slide contact portion on the rack side and a second slide contact portion. The first slide contact portion includes a first surface being inclined so as to displace the moving unit toward the rack. The second slide contact portion includes a second surface preventing the moving unit from being displaced toward the rack.