Separation Pad Mechanism for Low-Height Document Feeding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of a compression coil spring to press the separation pad against the sheet feed roller in document conveying devices increases the device height and requires a strong force to remove jammed sheets, potentially damaging them.
Innovation Solution
A document conveying device with a pad holder that can turn upward and downward, biased by a tension spring, and a separation pad support mechanism that allows the pad to be separated from the feed roller against the tension spring's bias, reducing the need for a separate drive source and minimizing the device's height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a compression coil spring is used to press the separation pad against the sheet feed roller, then the separation pad can be pressed with sufficient force, but the device height increases and strong force is required to remove jammed sheets
Solution Approach 1:
The patent inverts the conventional compression spring mechanism by using a tension spring instead. The tension spring is anchored to the frame above the sheet feed roller and pulls the pad holder upward, creating the pressing force through tension rather than compression. This inversion allows the separation pad to be pressed with sufficient force while eliminating the need for a compression spring disposed below the roller, thereby reducing device height.
Solution Approach 2:
The patent changes the spatial arrangement by moving the spring mechanism from a vertical compression arrangement (below the roller) to a horizontal/vertical tension arrangement (above the roller). The pad holder is configured to move horizontally away from the roller when released, utilizing horizontal space rather than vertical space, thus reducing the device height while maintaining the pressing force function.
2Reliability
If a compression coil spring is used to press the separation pad, then reliable separation is achieved, but the device height increases by the height of the spring
Solution Approach 1:
The patent inverts the conventional compression spring mechanism by using a tension spring instead. The tension spring is anchored to the frame above the sheet feed roller and pulls the pad holder upward, creating the pressing force through tension rather than compression. This inversion allows the separation pad to be pressed with sufficient force while eliminating the need for a compression spring disposed below the roller, thereby reducing device height.
3Reliability
If the separation pad is pressed strongly against the feed roller, then the uppermost sheet can be reliably separated, but a strong force is required to pull out jammed sheets
Solution Approach 1:
The patent makes the pressing force dynamic by allowing the pad holder to move horizontally away from the sheet feed roller when a sheet is jammed. The tension spring allows the pad to be pressed strongly during normal operation for reliable separation, but when jamming occurs, the pad can be easily pulled away horizontally, requiring minimal force to remove the jammed sheet. This dynamic adjustment resolves the contradiction between strong pressing force and easy jam removal.
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
The solution enables easy removal of jammed sheets with minimal force and reduces the device's height by about 8% compared to using a compression coil spring, enhancing operational efficiency and reducing sheet damage.
Implementation Method 1
The tension spring 55 biases the pad holder 51 upward to press the separation pad 35 against the feed roller 33
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A document conveying device (1) includes a feed roller (33), a separation pad (35), a pad holder (51), a tension spring (55), and a separation pad support mechanism (45). The feed roller (33) and the separation pad (35) form a separation nip at which a sheet is separated and conveyed. The pad holder (51) holds the separation pad (35) and can be turned upward and downward around a turning shaft (53). The tension spring (55) biases the pad holder (51) upward to press the separation pad (35) against the feed roller (33). The separation pad support mechanism (45) turns the pad holder (51) in a direction to separate the separation pad (35) from the feed roller (33) against a biasing force of the tension spring (55).