Printing System Conveyance Control for Skew Prevention
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Solution Overview
Problem
Existing printing systems with multiple devices face issues with paper slippage and varying slack amounts due to speed differences and paper size variations, leading to skew defects and conveyance delays, which are not adequately addressed by current control methods.
Innovation Solution
A printing system with a conveyance mechanism that includes a passage detection sensor, a conveyor roller, and a resist roller, where the conveyor roller is controlled to maintain a constant slack amount based on the conveyance status and detection time of the preceding medium, ensuring proper alignment and preventing skew defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional control methods are used for paper conveyance in multi-device printing systems, then device complexity is reduced, but manufacturing precision deteriorates due to varying slack amounts and skew defects
Solution Approach 1:
The resist roller is positioned upstream of the printing unit to pre-form slack in the paper before it reaches the printing area. This preliminary action of creating controlled slack prevents skew defects and ensures consistent paper positioning, directly improving manufacturing precision without requiring complex real-time control systems.
Solution Approach 2:
A passage detection sensor detects the passage of paper and provides feedback to the controller, which then adjusts the resist roller operation. This feedback mechanism enables the system to maintain constant slack amounts by dynamically responding to paper conveyance status, achieving high precision while keeping the control system relatively simple through intelligent feedback rather than complex mechanical structures.
2Productivity
If paper conveyance speed is increased to improve productivity, then printing productivity is improved, but reliability deteriorates due to paper collisions and jams
Solution Approach 1:
The resist roller creates controlled slack in the paper before it enters the printing unit, ensuring that paper sheets are properly spaced and aligned. This preliminary action prevents paper collisions and jams even at high conveyance speeds, maintaining reliability while enabling high productivity through smooth, collision-free paper flow.
Solution Approach 2:
The slack formed by the resist roller acts as a cushion between paper sheets during conveyance. This beforehand cushioning absorbs speed variations and prevents direct paper collisions, ensuring reliable conveyance at high speeds without jams or misalignment issues.
3Productivity
If resist roller is positioned closer to the printing unit to reduce conveyance distance, then printing productivity is improved, but manufacturing precision deteriorates due to insufficient slack formation
Solution Approach 1:
The resist roller is driven at variable speeds controlled by a controller that responds to feedback from a passage detection sensor. This dynamic control allows the system to maintain optimal slack formation regardless of the resist roller's position, achieving both high productivity and precise paper alignment even when the resist roller is positioned closer to the printing unit for efficient conveyance.
Data Source
AI summary
A printing system, including a first printing part, a second printing part that is disposed downstream of the first printing part in the conveying direction of a medium, and a conveyance mechanism that conveys the medium The conveyance mechanism includes a passage detection sensor, a conveyor roller, and a resist roller that is disposed downstream in the conveying direction from the passage detection sensor and the conveyor roller, that is butted by the medium, and that conveys the medium slackened due to the butting. The printing system further includes a controller configured to control the conveyor roller so that the slack amount of the subsequent medium is constant based on the conveyance status of the preceding medium and the detection time of the leading edge of the subsequent medium detected by the passage detection sensor.