Scanner Encoder Mounting for Thin Image Readers
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Solution Overview
Problem
Conventional image reading apparatuses face challenges in achieving high accuracy while minimizing size and thickness, as existing feedback control systems require additional space and components that increase the thickness of the scanner unit.
Innovation Solution
The apparatus incorporates a drive unit with a motor, gear train, encoder sensor, and support member, where the encoder sensor is securely fixed using a resilient member to reduce the overall thickness and size, and the drive unit is intensively disposed on the carriage to avoid overlapping with the image reading sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control with encoder is implemented for high reading accuracy, then reading accuracy is improved, but apparatus thickness increases
Solution Approach 1:
The encoder sensor is integrated directly into the support member structure, eliminating the need for separate encoder mounting boards. The resilient member (spring) is used to urge the encoder sensor against the support member, creating a compact assembly where the encoder is firmly held without requiring additional space in the thickness direction.
Solution Approach 2:
Instead of mounting the encoder sensor in the thickness direction (which would increase apparatus thickness), the encoder sensor is positioned to read the code wheel from the radial direction of the motor shaft. This dimensional reorientation allows the encoder to function properly while maintaining a compact thickness profile.
2Reliability
If drive unit is disposed at lower portion or side of carriage, then feedback control can be implemented, but scanner unit thickness becomes great
Solution Approach 1:
The drive unit components (motor, gear train, encoder sensor) are merged into a single integrated assembly mounted on the carriage. The encoder sensor is incorporated into the support member structure itself, and the resilient member provides both mounting and positioning functions, reducing the overall space required.
Solution Approach 2:
The resilient member (spring) provides dynamic adjustment capability, allowing the encoder sensor to be firmly held against the support member while accommodating manufacturing tolerances and assembly variations. This dynamic mounting approach eliminates the need for rigid, space-consuming mounting structures.
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 allows for high-accuracy image reading while significantly reducing the size and thickness of the apparatus, enhancing usability and miniaturization.
Implementation Method 1
the encoder sensor is urged against a part of the support member by a resilient member, to be thus fixed to the support member
Data Source
AI summary
An image reading apparatus includes a drive unit that is mounted on a carriage having an image reading sensor, which is moved with respect to an original, mounted thereon and moves the carriage. The drive unit includes: a motor; a gear train for transmitting rotation of the motor so as to move the carriage; an encoder sensor for reading a code wheel fixed to a rotary shaft of the motor; and a support member for holding the motor. The encoder sensor is urged against a part of the support member by a resilient member, to be thus fixed to the support member.