Sheet Stacking Lever Holding Mechanism for Breakage Prevention
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Solution Overview
Problem
In miniaturized image forming apparatuses, such as fax machines and printers, the sheet stacking levers can break when forces are applied beyond their rotation range, especially when the upper unit is opened, due to limited elasticity displacement, leading to potential breakage during sheet removal.
Innovation Solution
A sheet stacking apparatus with a lever held in a lower limit position by a holding portion that includes an engagement portion and an elastic portion, which releases the holding when a force is applied to prevent breakage by allowing the lever to move beyond its initial rotation range, thereby reducing back action and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the upper unit is opened upward to facilitate sheet removal, then the space from the rotating edge of the lever to the top surface of the sheet stacking portion becomes larger, but the lever may break if a force exceeding the rotation range is applied
Solution Approach 1:
The holding portion is designed to dynamically adjust its holding state based on the position of the upper unit. When the upper unit is closed, the holding portion holds the lever at the lower limit position to prevent breakage. When the upper unit is opened, the holding portion releases the lever to allow full rotation range, facilitating sheet removal. This dynamic adjustment resolves the contradiction between operation ease and reliability.
Solution Approach 2:
The holding portion changes its holding parameter (holding force or holding position) based on the state of the upper unit. By detecting whether the upper unit is closed or opened, the holding portion adjusts its holding strength accordingly - strong holding when closed to prevent breakage, weak or no holding when opened to allow sheet removal. This parameter change resolves the technical contradiction.
2Reliability
If a spring member is used to regulate the lower limit position of the lever, then the lever breakage is prevented when the upper unit is closed, but the lever may still break when the upper unit is opened due to limited elasticity displacement
Solution Approach 1:
The holding portion dynamically adjusts its holding state based on the position of the upper unit. When the upper unit is closed, the holding portion holds the lever at the lower limit position to prevent breakage. When the upper unit is opened, the holding portion releases the lever to allow full rotation range, facilitating sheet removal. This dynamic adjustment resolves the contradiction between operation ease and reliability.
Solution Approach 2:
The invention extracts the holding function from the spring member and concentrates it in the holding portion. The spring member only provides elastic displacement within a limited range, but the holding portion actively controls the lever position based on the upper unit state. This extraction allows the system to overcome the limitation of the spring member's fixed elasticity range.
3Volume of moving object
If the sheet stacking space size is reduced to miniaturize the apparatus, then the footprint is reduced, but the sheet stacking capacity is limited
Solution Approach 1:
The sheet pressing lever dynamically adjusts its pressing force based on the sheet stacking amount. When sheets are stacked, the lever presses down to compact them, maximizing the use of limited space. When sheets are removed, the lever releases the pressure. This dynamic adjustment allows the compact stacking space to accommodate varying sheet quantities efficiently.
Solution Approach 2:
The sheet pressing lever changes its pressing parameter (force magnitude) based on the stacking condition. By detecting the sheet stacking state, the lever adjusts its pressing strength to compact sheets tightly when space is needed, and releases when sheets are removed. This parameter change enables efficient use of the reduced stacking space.
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 prevents lever breakage by releasing the holding mechanism when excessive force is applied, allowing the lever to move safely and reducing the risk of damage during sheet removal, even when the upper unit is opened, thus enhancing the durability and functionality of the sheet stacking system.
Implementation Method 1
an elastic portion (5) which elastically deforms to release the holding of the sheet pressing lever (2) by the engagement portion (4)
Data Source
AI summary
A holding portion includes a engagement portion which holds a sheet pressing lever which presses from above a sheet discharged into a sheet stacking portion so that the engagement portion moves upward together with an image reading portion rotatably provided above an image forming portion, and an elastic portion which elastically deforms to release the holding of the sheet pressing lever by the engagement portion. If a force is applied to the sheet pressing lever being held by the holding portion in a direction which makes the lever rotate even lower than its lower limit position, the elastic portion elastically deforms to release the holding of the sheet pressing lever by the engagement portion.