Compact Drive Unit Assembly for Auto Document Feeder
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Solution Overview
Problem
Existing reading apparatuses with auto document feeders (ADFs) face issues of increased size due to dead space and reduced encoder detection accuracy caused by the placement of motors and encoder components, leading to positional deviations and soiling.
Innovation Solution
The reading apparatus is designed with a motor rotational shaft oriented parallel to the hinge axis, featuring a gear train aligned with the rotational shaft extension, and separate attachment of gears and code wheels at the shaft ends, reducing size and maintaining high encoder accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the DC motor is arranged apart at the back side of the apparatus across the transmission mechanism, then the transmission mechanism can be configured, but both sides of the DC motor form a large dead space and the area of the apparatus in the depth direction becomes uselessly large
Solution Approach 1:
The patent reorients the DC motor so that its rotational shaft extends in the width direction rather than the depth direction. This dimensional change allows the motor to be positioned within the ADF unit without creating dead space in the depth direction, thereby reducing the apparatus area in that dimension while maintaining transmission mechanism functionality.
2Device complexity
If the code wheel and worm gear are attached adjacent to each other on the rotational shaft of the DC motor, then the shaft can be utilized for both functions, but the rotational shaft needs to be made longer and positional deviation of the code wheel is amplified even when the rotational shaft has a slight inclination or bend
Solution Approach 1:
The patent extracts the code wheel from its traditional position adjacent to the worm gear and relocates it to the opposite end of the rotational shaft. This separation removes the code wheel from the region affected by shaft inclination and bending near the motor, thereby eliminating the amplification of positional deviation and maintaining encoder detection accuracy.
3Device complexity
If the code wheel is attached adjacent to the worm gear on the rotational shaft, then the structure can be compact, but grease used for lubrication of the worm gear is likely to adhere to the adjacent code wheel or encoder sensor, causing soiling and deterioration of detection accuracy
Solution Approach 1:
The patent extracts the code wheel from the vicinity of the worm gear and positions it at the opposite end of the rotational shaft. This spatial separation eliminates the contamination path for grease, allowing the worm gear to be lubricated without risking adherence of grease to the code wheel or encoder sensor, thereby preventing deterioration of detection accuracy.
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 achieves a compact design while ensuring high and sustained detection accuracy by minimizing dead space and preventing grease adherence, thus enhancing the compatibility of size reduction with accurate document reading.
Implementation Method 1
an encoder unit configured to detect rotation information of the motor, and including a sensor and a code wheel
Data Source
AI summary
A reading apparatus includes an auto document feeder configured to be openable and closable around a hinge with respect to a unit including an image sensor. The auto document feeder includes a roller configured to move a document relative to the image sensor, a motor, a gear train configured to transmit a rotation of a rotational shaft of the motor to the roller, and an encoder unit configured to detect rotation information of the motor, and including a sensor and a code wheel. An orientation of the rotational shaft is substantially parallel to a rotational axis of the hinge, and the gear train is arrayed in a direction of an extension of the rotational shaft. A gear that is a part of the gear train is attached to one end of the rotational shaft, and the code wheel is attached to the other end thereof.