Transport Roller Braking Load for Document Speed Disturbance
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Solution Overview
Problem
Image reading apparatuses face disturbances in document transport speed due to the trailing end of a document being tossed out from the nip position between the feed roller and separation device, leading to image singularities, which can be mitigated but at the cost of degraded document separation performance.
Innovation Solution
An image reading apparatus with a transport roller disposed upstream of the reading section and a load applying device that imparts a braking force against the transport roller's rotation, combined with a position regulator and lubricant retainer to reduce torsion and maintain stable sliding load, thereby suppressing disturbances in transport speed and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the load applied by the feed roller and separation device is reduced to prevent document tossing, then document separation performance is maintained, but transport speed disturbance is suppressed less effectively
Solution Approach 1:
The invention divides the load application into two independent parts: the feed roller/separation device nip load and the transport roller braking load. This segmentation allows each component to perform its specific function optimally - the nip maintains document separation while the braking load suppresses speed disturbance
Solution Approach 2:
The transport roller acts as an intermediary element between the feed roller and the reading section. By applying braking load to the transport roller, the system mediates the shock from document tossing before it reaches the reading section, protecting image quality while maintaining separation performance
2Reliability
If the load applied by the feed roller and separation device is increased to improve document separation, then document separation performance is improved, but transport speed disturbance increases
Solution Approach 1:
The invention separates the functions of document separation and speed stabilization into different components. The feed roller and separation device handle separation with appropriate nip load, while the transport roller with braking load handles speed stabilization, allowing both functions to operate at optimal load levels
Solution Approach 2:
The braking load on the transport roller provides preliminary counter-action to the speed disturbance caused by document tossing. By pre-applying a resistive force, the system prepares the transport roller to absorb shocks before they cause significant speed variations, thereby reducing image singularities
3Object-affected harmful factors
If a braking load is applied to the transport roller to suppress transport speed disturbance, then image quality is improved, but additional device complexity is introduced
Solution Approach 1:
The transport roller is designed to serve multiple functions: transporting documents, applying braking load for speed stabilization, and potentially driving the document through the system. This multi-functionality reduces the need for separate braking mechanisms, thereby limiting the increase in device complexity
Solution Approach 2:
The invention merges the braking function with the transport roller itself. By integrating the load applying device with the existing transport roller mechanism, the system combines document transport and speed stabilization into a single component, avoiding the need for entirely separate braking systems
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
Efficient suppression of document transport speed disturbances and enhanced accuracy by applying a braking force to the transport roller and optimizing the rotating shaft's position and lubrication, reducing the length of torsion and wear, while maintaining cost-effectiveness.
Implementation Method 1
a load applying device that applies a load against rotation of the transport roller
Implementation Method 2
a lubricant retainer that supplies a lubricant to the rotating shaft
Data Source
AI summary
An image reading apparatus includes a medium support section that supports a medium before feeding, a reading section that reads the medium that feeds from the medium support section, a transport roller that is disposed upstream of the reading section and transports the medium to the reading section, and a load applying device that applies a load against rotation of the transport roller. The transport roller is disposed on a rotating shaft that extends in a medium width direction that intersects the medium transport direction, and the load applying device imparts the load by pressing a transport roller driving gear that is disposed at one end of the rotating shaft in a direction from the one end of the rotating shaft to the other end thereof.