Scanner Line Sensor Biasing Mechanism for Warping Prevention
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Solution Overview
Problem
Existing scanner apparatuses with line sensor units biased by coil springs tend to warp, causing defocusing and streaky blurring in the read image, especially at the center, due to uneven contact with the glass plate.
Innovation Solution
A scanner apparatus design featuring a line sensor unit coupled with a holder, where two spacers on either side of the unit contact the transparent plate, and a biasing unit applies force between these spacers to maintain the line sensor's shape, preventing warping and ensuring even contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the line sensor unit is biased toward the glass plate by a coil spring with contact members at both ends, then the line sensor unit can be pressed against the glass plate, but the line sensor unit may be warped causing defocusing and streaky blurring at the center
Solution Approach 1:
The patent divides the biasing force application into segments: contact members at both ends provide support points, while a separate biasing member (coil spring) applies force at the center. This segmentation allows the line sensor unit to be pressed against the glass plate without warping, as the biasing force is applied through a dedicated path that prevents deformation of the sensor unit itself.
Solution Approach 2:
The patent introduces a biasing member (coil spring) as an intermediary element between the biasing force source and the line sensor unit. This intermediary applies the biasing force through a controlled mechanism that prevents direct warping of the line sensor unit, while still ensuring adequate contact with the glass plate.
2Reliability
If the line sensor unit is warped due to uneven contact, then the reading optical system focus shifts, but this causes imaging failure and blurring in the read image
Solution Approach 1:
The patent applies local quality by providing different functional characteristics at different locations: contact members at both ends provide structural support and stability, while the center area has the biasing member applied through a dedicated path that prevents warping. This local differentiation ensures that the line sensor unit maintains proper contact with the glass plate without warping, thereby preventing defocusing and imaging failures.
3Stability of the object's composition
If the line sensor unit is fixed to the holder at both ends, then the holder can be warped without affecting the line sensor unit, but this requires additional coupling portions
Solution Approach 1:
The patent segments the coupling structure into distinct elements: holder coupling portions at both ends that connect to the line sensor unit, and a separate biasing member that applies force through a dedicated path. This segmentation allows the line sensor unit to be stabilized without requiring complex integrated coupling structures, as each component has a specific, simplified function.
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 ensures clear, focused images across the entire document without partial imaging failures by maintaining the line sensor's shape and preventing defocusing.
Implementation Method 1
a biasing unit configured to bias the holder toward the transparent plate between the first spacer and the second spacer in the longitudinal direction
Data Source
AI summary
A scanner apparatus includes: a holder configured to hold a line sensor unit; a first spacer and a second spacer disposed on both sides of the line sensor unit in a longitudinal direction and configured to come into contact with the transparent plate; and a biasing unit configured to press the holder toward the transparent plate between the first spacer and the second spacer in the longitudinal direction. The line sensor unit and the holder are coupled together on both sides of the biasing unit in the longitudinal direction. A force applied to the holder by the biasing unit is transmitted from the holder through two coupling portions to the line sensor unit, thereby biasing the first spacer and the second spacer to the transparent plate.