Multi-Abutment Sheet Detection Lever for High-Speed Throughput
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Solution Overview
Problem
Conventional sheet detecting apparatuses in image forming systems face challenges in maintaining a short sheet-to-sheet distance as the conveying speed increases, leading to reduced throughput due to longer return times for the sensor lever.
Innovation Solution
A sheet detecting apparatus with a plurality of abutment surfaces and a mechanism involving a first and second rotary member with a specific speed ratio, along with an urging spring, allows for rapid positioning of abutment surfaces, enabling detection of the leading edge of a succeeding sheet within a short sheet-to-sheet distance even at higher conveying speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conveying speed of the sheet is increased to enhance throughput, then the productivity is improved, but the sheet-to-sheet distance becomes longer due to the sensor lever's return time, worsening the productivity
Solution Approach 1:
The sensor lever is divided into multiple segments (first rotary member and second rotary member) that can operate independently. The first rotary member detects the sheet while the second rotary member returns to the waiting position simultaneously, eliminating the sequential operation bottleneck and reducing the sheet-to-sheet distance required for detection.
2Productivity
If a single abutment surface is used on the sensor lever, then the device complexity is low, but the sheet detecting apparatus cannot return to the waiting position quickly enough for high conveying speeds, worsening the productivity
Solution Approach 1:
The sensor lever structure is segmented into multiple functional components: a first rotary member with abutment surfaces for sheet detection, a second rotary member for returning to the waiting position, and an urging spring mechanism. This segmentation allows simultaneous detection and reset operations, enabling high-speed conveying.
Solution Approach 2:
The sensor lever transitions from a static single-abutment design to a dynamic multi-component system where the first and second rotary members can rotate independently at different speeds and directions. This dynamic structure enables the abutment surfaces to be rapidly repositioned for successive sheet detection.
3Reliability
If the sensor lever rotates to return to the waiting position after a sheet passes, then the detection function is maintained, but the time required for return rotation increases the sheet-to-sheet distance, worsening the productivity
Solution Approach 1:
The urging spring is pre-loaded to store elastic energy that automatically drives the second rotary member to rotate and position the abutment surfaces for the next sheet detection. This preliminary energy storage eliminates the need for active motor control during the return stroke, reducing response time and enabling faster throughput.
Solution Approach 2:
While the first rotary member completes its detection rotation, the second rotary member simultaneously returns to the waiting position using the urging spring's elastic force. These actions occur in parallel rather than sequentially, maintaining continuous detection capability without idle return time, thus improving productivity.
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
This configuration reduces the time between the passage of a preceding sheet and the positioning of the sheet detecting member for the succeeding sheet, allowing for reliable detection and maintaining a short sheet-to-sheet distance, thereby enhancing the throughput of the image forming apparatus.
Implementation Method 1
an urging spring which provides the sheet detecting member with an urging force for positioning the one of the plurality of abutment surfaces in the waiting position
Implementation Method 2
a detection sensor 524, a light-shielding portion 525 which shields an optical path from a light-emitting portion to a light-receiving portion of the detection sensor 524 from light
Data Source
AI summary
A sheet detecting apparatus including: a sheet detecting member having a plurality of abutment surfaces in a peripheral direction thereof, the sheet detecting member being rotated by a conveyed sheet abutting against one of the plurality of abutment surfaces; a detection portion which operates in association with the sheet detecting member; a sensor which generates a signal based on a position of the detection portion; and an urging portion which generates an urging force for positioning the one of the plurality of abutment surfaces of the sheet detecting member in a waiting position in which the leading edge of a sheet conveyed by a conveying portion abuts against the one of the plurality of abutment surfaces, and thereafter the urging portion switching the urging force to an urging force for positioning, in the waiting position, another one of the plurality of abutment surfaces against which a succeeding sheet abuts.