Sheet Detecting Device Segmented Contact Member Rotation
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Solution Overview
Problem
Existing sheet detecting devices in image forming apparatuses face challenges in detecting small sheet intervals while minimizing damage to the leading end of the sheet and maintaining high positional accuracy.
Innovation Solution
A sheet detecting device with a contact member that rotates upon sheet contact, a detection member attached to the contact member, a sensor to detect the rotation, a first urging member to act on both, and a stopper for the detection member, allowing the contact member to further rotate relative to the detection member after initial contact, reducing the moving distance of the detection member and enhancing positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection flag is disposed coaxially with the conveyance roller to reduce rotational angle, then small sheet interval detection is enabled, but the leading end of the sheet may be damaged due to concentrated force
Solution Approach 1:
The detection flag is divided into a contact member (rotatable by sheet) and a detection member (attached to contact member), separating the force reception function from the detection function. This segmentation allows the contact member to rotate and absorb force while the detection member remains relatively stationary, reducing damage to the sheet while maintaining detection precision.
Solution Approach 2:
The contact member acts as an intermediary between the sheet and the detection member. It receives the sheet's force, converts it to rotational motion, and transmits only the rotational information to the detection member, protecting the sheet from direct force concentration while enabling precise detection.
2Reliability
If the detection member is made to move a large distance to detect sheet passage, then detection reliability is improved, but positional accuracy deteriorates
Solution Approach 1:
The system uses dynamic rotational motion of the contact member instead of linear displacement of the detection member. The contact member rotates dynamically in response to sheet passage, while the detection member remains relatively fixed, achieving both reliability through motion and precision through minimal displacement.
Solution Approach 2:
The invention changes the detection parameter from linear displacement distance to rotational angle. The contact member's rotational angle serves as the detection parameter, allowing reliable detection with minimal movement, thereby maintaining high positional accuracy while ensuring detection reliability.
3Loss of time
If the detection flag returns quickly to the initial position, then small sheet interval detection is enabled, but the configuration becomes complex
Solution Approach 1:
The contact member and detection member are merged into a single integrated assembly that rotates together initially. This merging simplifies the mechanism by eliminating the need for separate return mechanisms, while still achieving quick reset through the natural rotational motion and urging spring action.
Solution Approach 2:
The detection mechanism uses the sheet's own passage to drive the return motion. As the sheet passes and the urging spring acts on the contact member, the entire assembly automatically returns to its initial position without requiring additional actuators or complex control mechanisms.
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 detection of small sheet intervals with reduced damage to the leading sheet end and improved positional accuracy, achieving a compact design and efficient operation.
Implementation Method 1
the detection flag returns to the standby position by the urging force of the urging spring
Implementation Method 2
a sensor configured to detect rotation of the detection member
Data Source
AI summary
After a detection flag and a detection member are integrally rotated as a result of the detection flag being pushed by a sheet, the detection flag is rotated relative to the detection member, with the detection member being in contact with an abutting portion.