Sheet Feeding Apparatus Weight-Based Pressure Control
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Solution Overview
Problem
In sheet feeding apparatuses, as the stacking amount of sheets decreases, the deformation of spring members reduces, leading to decreased restoring force and contact pressure of the feed roller, potentially causing feeding failures, especially when sheets need to climb an inclined guide portion during feeding.
Innovation Solution
A sheet feeding apparatus with an urging mechanism that includes a swinging member and a holding member, where the swinging member and holding member share a common axis, and a weight is used to increase the contact pressure of the feed roller with the sheet, ensuring consistent feeding even when the sheet stacking is low by adjusting the force based on the distance between the loading surface and the feed roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring member is used to pressurize the feed roller, then the feed roller can contact the sheet stack with restoring force, but as the stacking amount decreases, the deformation amount of the spring member decreases and the contact pressure decreases, potentially causing feeding failure
Solution Approach 1:
The patent changes the parameter of pressing force from constant (spring-based) to variable (weight-based) to adapt to different sheet stacking conditions. By using a weight that generates constant pressing force regardless of sheet stack height, the system maintains reliable feeding even when the stack is low, resolving the contradiction between feeding reliability and contact pressure stability.
2Ease of operation
If the separation nip is located higher than the loading surface with an inclined guide portion, then sheets can be conveyed while being separated one by one, but as the stacking amount decreases, the distance the sheet climbs increases and conveyance resistance increases
Solution Approach 1:
The patent applies preliminary anti-action by increasing the pressing force of the feed roller on sheets with small stacking amounts. This compensates for the increased conveyance resistance that occurs when sheets must climb the inclined guide portion over a longer distance, preventing feeding failures while maintaining the beneficial sheet separation function of the elevated separation nip.
3Productivity
If the feed roller is positioned above the loading surface, then sheets can be fed in the sheet feeding direction, but the distance between the loading surface and feed roller increases as stacking decreases, requiring more pressing force
Solution Approach 1:
The patent uses a weight as a counterbalancing mechanism to generate consistent pressing force on the feed roller. This weight-based system compensates for the increased distance between the loading surface and feed roller that occurs when sheet stacking is low, ensuring sufficient pressing force is maintained to enable continuous productive sheet feeding.
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 effectively reduces the likelihood of feeding failures by maintaining adequate contact pressure and conveying force as the sheet stacking decreases, ensuring stable feeding of sheets, including those with high stiffness or large grammage, by increasing the pressing force when the stacking amount is low.
Implementation Method 1
a weight (46) attached to the swinging member (37), wherein the holding member (29) is configured to be urged in a direction in which the feeding member (21) is brought into contact with the upper surface of the sheet by the swinging member (37) being urged due to a gravity acting on the weight (46)
Data Source
AI summary
A sheet feeding apparatus includes an urging mechanism configured to urge a holding member such that a feeding member is brought into contact with an upper surface of a sheet loaded on a sheet loading member by the holding member. The urging mechanism includes a swinging member, a pressing member, and an urging member. The urging mechanism is configured to urge the holding member such that (i) a force by which the feeding member presses an upper surface of a sheet in a first state in which a distance between a loading surface and the feeding member is a first distance is larger than (ii) a force by which the feeding member presses an upper surface of a sheet in a second state in which the distance between the loading surface and the feeding member is a second distance longer than the first distance.