Image Reading Apparatus Bidirectional Drive Mechanism
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Solution Overview
Problem
Existing image reading apparatuses are limited by a single-direction motor drive, which restricts functionality in both flatbed (FB) and automatic document feeder (ADF) modes, preventing reverse rotation and limiting features like document skew correction and double-sided reading.
Innovation Solution
An image reading apparatus with a common motor driving both modes, utilizing a planetary gear device and switching unit to enable forward and reverse rotation, allowing for seamless switching between FB and ADF modes without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a motor is driven in only one direction to simplify the driving system, then the device complexity is reduced, but the functionality is limited (cannot perform reverse rotation operations)
Solution Approach 1:
The patent applies the dynamics principle by making the gear engagement relationship changeable rather than fixed. The switching unit dynamically engages or disengages the pinion gear with different racks based on the required operation mode, enabling the system to switch between forward and reverse rotation capabilities while maintaining a relatively simple motor structure.
2Ease of manufacture
If a common motor is used for both ADF and FB modes to reduce cost, then the manufacturing cost is reduced, but the system must handle complex bidirectional driving requirements
Solution Approach 1:
The patent applies segmentation by dividing the driving system into separate functional components: a common motor, a switching unit, and multiple independent racks (first rack for FB mode, second rack for ADF mode). This segmentation allows the single motor to control multiple functions through the switching unit that selectively engages different racks, reducing cost while managing complexity through modular design.
Solution Approach 2:
The switching unit acts as an intermediary between the common motor and the two different reading mechanisms. It mediates the transmission of driving force by selectively engaging the pinion gear with either the first rack or the second rack, enabling the single motor to control both FB and ADF modes without direct complex coupling.
3Adaptability or versatility
If the reading unit moves to enable mode switching, then the system can switch between FB and ADF modes, but the positioning precision must be maintained during movement
Solution Approach 1:
The patent applies preliminary action by positioning the reading unit at predetermined positions before mode switching occurs. The switching unit is designed to engage with the pinion gear only when the reading unit is at the correct position, ensuring that mode switching is performed with proper positioning. This preliminary positioning action maintains reading precision while enabling mode switching.
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
Enables full functionality in both modes, including reverse rotation and double-sided reading, enhancing performance by maintaining cost-effectiveness.
Implementation Method 1
utilizing a planetary gear device and switching unit to enable forward and reverse rotation
Implementation Method 2
a reading unit which is rectilinearly movable by means of a rack and pinion gear
Data Source
AI summary
An image reading apparatus comprises a reading unit including a movable sensor, a first reading mechanism which moves the reading unit to read an original placed on a platen, a second reading mechanism which conveys the original relative to the reading unit to read the original, a common driving source which drives the first reading mechanism and the second reading mechanism, a transfer unit which transfers a driving force from the driving source to the first reading mechanism and the second reading mechanism, and a switching unit which switches rotation used to drive the second reading mechanism to one of forward rotation and reverse rotation with respect to rotation of the driving source in one direction, the switching unit operating as the reading unit moves.