Sheet Stacker Tray Position Control via Pause Sensors
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Solution Overview
Problem
Existing sheet stackers in image forming apparatuses can collide with components due to automatic lifting and lowering mechanisms, potentially damaging parts, as they lack precise control over tray positions, leading to unintended interactions.
Innovation Solution
Incorporating a lifting mechanism with an upper-limit sensor, lift pause sensor, lower-limit sensor, and lowering pause sensor to control the tray's position accurately, preventing collisions by stopping the lifting or lowering operation when reaching predefined pause positions, ensuring safe operation within specified ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sheet pallet is automatically lifted or lowered to control sheet stacking height, then the sheet stacking capability is improved, but the risk of collision with components increases
Solution Approach 1:
The patent applies preliminary action by installing pause sensors (upper pause sensor and lower pause sensor) at predetermined positions before the lift-limit sensor and lower-limit sensor, respectively. These pause sensors detect when the sheet pallet reaches safe pause positions during lifting or lowering operations, allowing the controller to temporarily halt the pallet's movement in advance to prevent potential collisions with components, while still enabling automatic height control for sheet stacking.
Solution Approach 2:
The patent uses pause sensors as intermediary detection devices between the lifting mechanism and the lift-limit sensor. The pause sensors act as intermediaries that provide early warning signals to the controller, enabling intermediate stopping points during the lifting/lowering process. This intermediary detection system allows the system to balance automatic operation with collision prevention by introducing additional safety layers without completely disabling automation.
2Ease of operation
If the sheet pallet is controlled to lift and lower automatically, then the operation convenience is improved, but the device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the sheet pallet to automatically lift and lower based on sheet stacking conditions without requiring manual operator intervention. The controller monitors sheet height and autonomously activates the lifting mechanism, while the pause sensors automatically trigger intermediate stops when predetermined positions are reached. This self-service system maintains operational convenience while managing complexity through automated decision-making based on sensor inputs.
3Productivity
If the sheet pallet is lowered continuously as sheets are stacked, then the stacking efficiency is improved, but the risk of component damage increases
Solution Approach 1:
The patent applies preliminary action by positioning the lower pause sensor at a predetermined height above the lower-limit sensor, creating an early warning system before the pallet reaches dangerous positions. This allows the controller to initiate intermediate stopping points during continuous lowering operations, preventing the pallet from colliding with components while maintaining efficient continuous stacking capability.
Solution Approach 2:
The patent implements feedback by using pause sensors to continuously monitor the sheet pallet's position during lifting and lowering operations. When the pallet approaches predetermined pause positions, the sensors provide feedback signals to the controller, which then adjusts the pallet's movement by introducing temporary stops. This feedback mechanism ensures component safety while allowing continuous stacking operations to proceed efficiently between safe zones.
Data Source
AI summary
A sheet stacker includes a lifting mechanism, a tray, a conveyor, processing circuitry, an upper-limit sensor, a lift pause sensor, a lower-limit sensor, and a lowering pause sensor. The tray stacks multiple sheets. The conveyor above the tray conveys a sheet. The processing circuitry controls, via the lifting mechanism, a height position of the tray. The upper-limit sensor detects that an uppermost sheet of the sheets has reached an upper-limit position. The lift pause sensor detects that the uppermost sheet has reached a lift pause position lower than the upper-limit position. The lower-limit sensor detects that the tray has reached a lower-limit position. The lowering pause sensor detects that the tray has reached a lowering pause position higher than the lower-limit position. The upper-limit sensor, the lift pause sensor, the lower-limit sensor, and the lowering pause sensor are disposed in a space in which the tray is lifted and lowered.