Sheet Stacking Apparatus Velocity Difference Control
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Solution Overview
Problem
Existing sheet stacking apparatuses in image forming apparatuses suffer from low stacking efficiency and poor stack alignment due to sheets falling freely, which lengthens fall times and causes non-uniform fall positions, and there are concerns about sheet damage from stoppers and increased complexity and cost.
Innovation Solution
A sheet stacking apparatus that uses a control portion to control the movement velocity of a moving portion to be higher than the sheet discharge velocity, allowing the sheet to be separated from the gripper using a velocity difference, thereby landing on a stacking portion by inertia, reducing reliance on weight-induced fall and simplifying the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sheets are allowed to fall freely under gravity, then the stacking apparatus structure is simplified, but the fall time increases and stack alignment deteriorates
Solution Approach 1:
The invention changes the velocity parameter of the moving portion to be higher than sheet discharge velocity, creating a velocity difference that enables sheet separation without gravity-dependent free fall. This parameter change allows the sheet to be quickly discharged onto the stacking portion while maintaining alignment, resolving the contradiction between simplified structure and precision stacking.
2Manufacturing precision
If a mechanism is added to press falling sheets from above, then stack alignment improves, but the apparatus becomes complicated and increases in size
Solution Approach 1:
The invention extracts the need for complex pressing mechanisms by using velocity difference-based separation. The sheet is discharged onto the stacking portion by the inertial force generated from the velocity difference, eliminating the requirement for additional pressing devices and maintaining both simplicity and alignment precision.
3Ease of operation
If the gripper is bumped against the stopper to separate the sheet, then sheet separation is achieved, but the front end portion of the sheet may be damaged
Solution Approach 1:
The invention replaces the mechanical bumping system with a velocity difference-based separation system. Instead of mechanically impacting the gripper against a stopper, the moving portion is controlled to move faster than the sheet discharge, creating a velocity difference that naturally separates the sheet without impact or damage to the front end portion.
4Object-affected harmful factors
If the movement velocity of the moving portion is made higher than sheet discharge velocity, then sheet separation is achieved without stopper impact, but control complexity increases
Solution Approach 1:
The control portion serves multiple functions: it controls both the discharging portion and the moving portion, and it manages the velocity difference between them to achieve sheet separation. This multi-functionality avoids the need for separate control systems for each component, maintaining control simplicity while achieving damage-free separation.
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 approach improves stacking efficiency and alignment by stabilizing and quickening the sheet stacking process without increasing the apparatus size, reducing sheet damage, and maintaining productivity.
Implementation Method 1
separates the sheet from the moving portion by using a velocity difference between the movement velocity and the sheet discharge velocity
Data Source
AI summary
A sheet stacking device has a discharging portion, a holding portion that holds a downstream end portion of the sheet, a stacking portion and a control portion that controls the discharging portion and the holding portion. The control portion controls at least one of the discharging portion and a holding portion so that the movement velocity of the holding portion is higher than the sheet discharge velocity of the discharging portion, and separates the sheet from the holding portion by using a velocity difference between the movement velocity and the sheet discharge velocity.