Sheet Discharging Device with Dynamic Pressing Force Control
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Solution Overview
Problem
Existing sheet discharging devices face challenges in reliably conveying a wide variety of sheets, including curled and glossy papers, due to issues with friction and curling, leading to incomplete discharge and potential jamming, especially with increased speeds and color usage in image forming apparatuses.
Innovation Solution
A sheet discharging device with a caterpillar belt and a plate-like guide member, where the pressing force is adjusted by a conveying weight and paddle mechanism to ensure proper transfer, using a rubber piece on a paddle driving shaft to engage and press the conveying weight at specific times, allowing for reliable conveyance of sheets onto a tray without damaging them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the conveyance guide is reduced to allow a sheet to advance more easily between the conveyance guide and the belt top surface, then thin sheets can advance more easily, but thick glossy paper may have its trailing end remain on the belt causing incomplete discharge
Solution Approach 1:
The conveyance guide is designed to be movable rather than fixed, allowing it to dynamically adjust its position and pressing force based on the sheet being conveyed. This enables the guide to apply appropriate pressing force for thick glossy paper while maintaining ease of advancement for thin sheets, resolving the contradiction between ease of operation and discharge completeness
Solution Approach 2:
The pressing force of the conveyance guide is made variable rather than constant. By changing the pressing force parameter according to sheet type and position in the conveyance process, the system achieves both easy advancement for thin sheets and complete discharge for thick glossy paper without compromising either requirement
2Reliability
If the pressing force of the conveyance guide is increased to prevent curled thin sheets from advancing, then sheet discharge reliability improves, but jamming occurs with curled sheets
Solution Approach 1:
The conveyance guide's pressing force is made dynamic, adjusting automatically based on sheet characteristics and conveyance stage. This prevents excessive pressing that would cause jamming of curled sheets while maintaining sufficient pressing force to prevent loss of thin sheets, thereby improving reliability without generating harmful jamming effects
Solution Approach 2:
The system performs preliminary detection and adjustment of pressing force before the sheet enters the critical conveyance zone. By preparing the appropriate pressing force in advance based on sheet type, the system prevents both jamming and loss without requiring excessive pressing force that would cause harmful effects
3Reliability
If the contact force between the belt bottom surface and the tray is increased to reliably transfer sheets to the predetermined position, then transfer reliability improves, but accumulated sheets may be damaged such as wrinkling
Solution Approach 1:
The contact force between the belt bottom surface and the tray is made dynamic rather than constant. The force is adjusted according to the sheet being transferred and the number of sheets already on the tray, ensuring reliable transfer positioning while preventing excessive force that would cause damage such as wrinkling to accumulated sheets
Solution Approach 2:
The pressing force parameter is varied during the transfer process based on real-time conditions. By changing the force parameter adaptively, the system achieves reliable transfer to the predetermined position without applying harmful excessive force that would damage the sheets
4Object-affected harmful factors
If a decrease in contact force is applied to avoid damaging accumulated sheets, then sheet damage is prevented, but sheets cannot be reliably transferred to the predetermined position
Solution Approach 1:
The contact force is made dynamic, automatically adjusting between higher force for reliable transfer and lower force for damage prevention based on the specific transfer conditions. This resolves the contradiction by applying appropriate force levels at different stages rather than using a fixed force level
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 ensures reliable and efficient transfer of sheets to a predetermined position on the tray, preventing incomplete discharge and jamming, even with slippery or curled sheets, while maintaining a simple structure and easy operation.
Implementation Method 1
sheets the surfaces of which are coated exert only a small frictional force and are thus difficult to convey
Implementation Method 2
a sheet from the sheet discharging port is conveyed on a top surface of the belt to the tray
Data Source
AI summary
A sheet discharging device has a conveying weight for pressing a conveyed sheet to a caterpillar belt. The pressing force of the weight is increased both when the sheet is discharged from the caterpillar belt to a placement tray, and when the sheet is switched back and conveyed to the bottom of the caterpillar belt. The pressing force of the weight is increased concurrently with the driving of a paddle provided at an outlet of the placement tray. The pressing force is increased by a rubber piece provided on a paddle driving shaft that rotates out of phase with the paddle, so as to engage and press the conveying weight at a predetermined time. The device is capable of reliably conveying a wide variety of sheets onto a tray and transferring the conveyed sheets to a predetermined tray position.