Sheet Conveyance Control for Uninterrupted Printing
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Solution Overview
Problem
In image forming apparatuses, stopping continuous printing to move the sheet stack carriage to a post-process position before the specified number of prints is stacked leads to decreased efficiency, as it interrupts the printing process.
Innovation Solution
The apparatus includes a control device that manages a sheet conveyance device and lift mechanism, allowing the sheet stack carriage to be moved mid-stacking without stopping the print process by switching between stack and relay conveyance states and controlling the lift mechanism to adjust the stack tray position, enabling continuous printing while stacking sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet stack carriage is moved to the post-process position before the specified number of prints is stacked, then the post-process can be performed on time, but the continuous printing must be stopped which decreases production efficiency
Solution Approach 1:
The coupled units are divided into multiple independent units (first coupled unit, second coupled unit, etc.), each capable of independent sheet stacking. This segmentation allows one unit to perform post-process while another continues stacking, resolving the contradiction between timely post-process and continuous printing efficiency
Solution Approach 2:
The system enables continuous printing to proceed without interruption by coordinating multiple coupled units. While one unit's sheet stack carriage is moved for post-process, another unit continues stacking sheets, maintaining the continuity of the printing process and eliminating idle time
2Productivity
If the sheet stack carriage is moved during the middle of stacking the specified number of sheets, then continuous printing can be maintained, but the control complexity increases
Solution Approach 1:
The control device monitors the stacking status and carriage position in real-time, using feedback signals to determine when to initiate carriage movement. This feedback mechanism enables automatic coordination between stacking and movement operations, managing control complexity through intelligent monitoring rather than complex mechanical design
Solution Approach 2:
The control device is configured to initiate carriage movement at predetermined timing - specifically when the number of stacked sheets reaches a certain threshold or when the next coupled unit is ready to receive sheets. This preliminary action planning simplifies control by using pre-determined decision points rather than continuous complex calculations
Data Source
AI summary
A control device executes: either a first conveyance change control or a second conveyance change control; and a retraction control when an operation device receives an interruption operation during execution of a specified number stack control. In the first conveyance change control, a sheet conveyance device of a target unit is changed to a relay conveyance state, and the sheet conveyance device of another coupled unit that is present downstream of the target unit in a main conveyance direction is changed to a stack conveyance state. In the second conveyance change control, the sheet conveyance device of another coupled unit that is present upstream in the main conveyance direction is changed to the stack conveyance state. In the retraction control, a lift mechanism of the target unit is caused to execute a mount operation by which a stack tray is moved down to a mount position on a carriage portion.