Compact Punching Unit With Overlapping Eccentric Cam And Guide
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Solution Overview
Problem
Existing sheet post-processing devices are not compact due to the size and complexity of their punching units, which hinder efficient integration with image forming apparatuses.
Innovation Solution
A compact punching unit design incorporating a punching blade, holder, biasing member, eccentric cam, and punching guide, where the eccentric cam rotates to move the holder and blade in a retracting or punching direction, overlapping with the guide to minimize unit height and ensure smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional punching unit design is used, then the punching function is achieved, but the unit height becomes large and the device is not compact
Solution Approach 1:
The punching guide extends in the sheet conveyance direction (horizontal dimension) rather than vertically, allowing the punching blade to move horizontally through the guide. This dimensional reorientation reduces the vertical height of the punching unit while maintaining the punching function, directly resolving the contradiction between compactness and operational reliability.
2Volume of moving object
If the eccentric cam overlaps with the punching guide, then the unit height is minimized, but structural complexity increases
Solution Approach 1:
The eccentric cam is positioned to overlap with the punching guide in the sheet conveyance direction, merging the rotational motion path of the cam with the linear path of the punching guide. This spatial merging allows the holder to be driven efficiently by the cam while the punching blade moves through the guide, achieving compact height without excessive structural complexity.
Solution Approach 2:
The eccentric cam converts rotational motion into reciprocating linear motion of the holder dynamically. As the cam rotates, its eccentric profile automatically generates the forward and return strokes needed for punching and retraction, eliminating the need for additional mechanical components and simplifying the overall mechanism while maintaining compact dimensions.
3Productivity
If the punching blade moves rapidly, then productivity increases, but rattling and vibration increase
Solution Approach 1:
The punching guide acts as an intermediary component that constrains the punching blade's motion to a precise linear path. By guiding the blade through its reciprocating movement, the guide reduces lateral vibrations and rattling, allowing the blade to move rapidly for high productivity while minimizing harmful vibrations and noise.
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 design achieves a compact punching unit that reduces height and minimizes rattling, enabling efficient integration and smooth punching processes in image forming apparatuses.
Implementation Method 1
The biasing member biases the holder in a retracting direction in which the punching blade moves away from the sheet
Implementation Method 2
The eccentric cam contacts the holder, and rotates against a biasing force of the biasing member to move the holder in a punching direction in which the punching blade approaches the sheet
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A punching unit (2) includes a punching blade (31), a holder (33), a biasing member (34), an eccentric cam (35), and a punching guide (32). The eccentric cam (35) contacts the holder (33), and rotates against a biasing force of the biasing member (34) to move the holder (33) in a punching direction in which the punching blade (31) approaches the sheet. The punching guide (32) extends in a moving direction of the punching blade (31) in which the punching blade (31) moves with respect to the sheet, and guides movement of the punching blade (31). The eccentric cam (35), when moving the holder (33) in the punching direction, passes by a side of the punching guide (32) in a manner overlapping with the punching guide (32) as seen from a rotation axis direction of the eccentric cam (35).