Sheet Detection Lever Mechanism for High-Speed Conveyance
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Solution Overview
Problem
Conventional sheet detecting apparatuses in image forming systems face limitations in throughput enhancement due to the time required for the lever member to return to its home position, which increases the sheet-to-sheet distance as conveying speed increases, restricting the ability to enhance sheet conveyance throughput.
Innovation Solution
A sheet detecting apparatus with a lever member and a holding member that move integrally, utilizing first and second urging portions to facilitate the lever member's movement from a retracted position to abut a succeeding sheet's leading edge immediately after a trailing edge passes, allowing the sheet to pass and reducing the time between sheet passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lever member is returned to the home position by a return spring after the sheet passes, then the lever member can detect the leading edge of the next sheet, but the time required for the lever member to return to the home position increases the sheet-to-sheet distance, restricting throughput enhancement
Solution Approach 1:
The lever member is designed to dynamically change its position based on sheet passage. It moves from a first position (protruding into the sheet conveying path) to a second position (retracted) automatically in response to sheet trailing edge passage, eliminating the need for a return spring and reducing return time. This dynamic adaptation allows the lever member to quickly reset for detecting the next sheet's leading edge, thereby increasing throughput without increasing sheet-to-sheet distance.
2Productivity
If the conveying speed is increased to enhance throughput, then more sheets can be processed per unit time, but the sheet-to-sheet distance increases due to the lever member's return time, limiting further throughput improvement
Solution Approach 1:
The return spring mechanism is extracted from the system and replaced with a passive dynamic positioning mechanism. The lever member's return motion is achieved through the sheet's own trailing edge pushing it back to the retracted position, rather than requiring an active return force. This extraction of the return spring eliminates the time delay associated with spring-driven return motion, allowing higher conveying speeds to be maintained without increasing sheet-to-sheet distance, thus enabling sustained throughput enhancement.
3Measurement precision
If the lever member is positioned to abut against the leading edge of the sheet, then accurate detection of the leading edge is achieved, but the lever member must be completely retracted after sheet passage, increasing the reset time
Solution Approach 1:
The lever member is preliminarily positioned in a retracted state before the sheet trailing edge arrives. When the trailing edge contacts the lever member, it automatically pushes the lever member into the retracted position in advance of complete sheet passage. This preliminary action ensures that the lever member is already positioned to detect the next sheet's leading edge accurately while minimizing the time the lever member remains in the extended detection position, thereby reducing reset time without compromising detection accuracy.
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 enables higher throughput by minimizing the sheet-to-sheet distance and reducing the time for the lever member to return to its home position, even at higher conveying speeds, thus enhancing the efficiency of sheet conveyance.
Implementation Method 1
a urging spring configured to urge the lever member to return to the home position
Implementation Method 2
an optical sensor configured to detect a position of the lever member, the optical sensor including a light emitting portion and a light receiving portion
Data Source
AI summary
A sheet detecting apparatus has an abutment member against which a leading edge of a conveyed sheet abuts, a holding member with a positioning portion to hold the abutment member, and an indicator flag moving in association with movement of the abutment member. The abutment member moves between an abutment position and a retracted position, the holding member moves between a first position and a second position retracted from the first position, the abutment member is pushed by the leading edge of the sheet when the holding member is at the first position, with the push moving the holding member to the second position, the holding member is moved in a direction away from the first position so that the leading edge of the sheet is separated from the abutment surface, and the holding member moves from the second position to the first position when the abutment member is pushed by the sheet to the retracted position.