Airflow Control in Inkjet Printing via Segmented Vacuum Zones
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet printing systems using vacuum suction for media transport often experience image blurring due to air currents induced by uncovered holes near the edges of the print media, leading to inaccurate placement of ink droplets and reduced print quality.
Innovation Solution
An airflow control system is implemented, featuring upstream and downstream valves that can be transitioned between open and closed states, and individually addressable channels that supply vacuum suction to columns of holes, allowing for selective control of airflow to reduce crossflows and prevent blurring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum suction is used through holes in the media transport device to hold and transport print media, then the print media can be securely held in place without slippage and kept flat during transport, but air currents are induced through uncovered holes near the edges of the print media causing image blurring
Solution Approach 1:
The vacuum plenum is divided into multiple independently controllable vacuum zones separated by partitions. Each zone can be independently activated or deactivated based on the position of the media, allowing vacuum suction to be applied only where needed while preventing air currents in other zones that would cause image blurring.
Solution Approach 2:
The system dynamically controls the activation of vacuum zones based on the real-time position of the media during transport. By selectively enabling or disabling specific vacuum zones as media enters or exits the deposition region, the system maintains reliable media holding when needed while eliminating harmful air currents when media is not present, thus resolving the contradiction between media stability and image precision.
2Adaptability or versatility
If holes are arranged to extend across the full width of the deposition region to accommodate various media sizes, then any size of print media can be held, but uncovered holes appear adjacent to the inboard edge of smaller media causing air currents and blurring
Solution Approach 1:
The vacuum system is segmented into multiple independently controllable zones along the width of the deposition region. This allows selective activation of only those vacuum zones necessary for the current media size, preventing uncovered holes and air currents at the edges of smaller media while maintaining full-width coverage capability for larger media.
Solution Approach 2:
Different regions of the vacuum plenum have different operational states based on local needs. By applying vacuum suction only in the specific zones where media is present and adjusting the coverage dynamically, the system adapts to various media sizes without creating harmful air currents in uncovered regions, thus maintaining both versatility and precision.
3Reliability
If vacuum suction is maintained continuously to hold media throughout the deposition region, then media transport stability is ensured, but air currents are generated in inter-media zones causing crossflows that deflect ink droplets
Solution Approach 1:
Vacuum suction is applied periodically rather than continuously, with specific vacuum zones activated only when media is present in those regions. By synchronizing vacuum activation with media position, the system maintains media stability during transport while eliminating unnecessary vacuum-induced air currents in inter-media zones during ink deposition, preventing crossflows that would deflect ink droplets.
Solution Approach 2:
The vacuum system dynamically adjusts its operation based on media position and deposition phase. During ink deposition, vacuum zones are selectively deactivated or reduced in intensity in areas where media is not present, eliminating harmful air currents while maintaining media holding stability where needed, thus resolving the contradiction between transport reliability and prevention of ink deflection.
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 airflow control system effectively reduces or eliminates crossflows, ensuring that ink droplets are deposited accurately, thereby improving the clarity and precision of printed images while maintaining efficient printing speeds.
Implementation Method 1
the vacuum source creates a vacuum state in the vacuum plenum, causing vacuum suction through holes in the movable support surface that are fluidically coupled to the vacuum plenum
Implementation Method 2
The upstream valve blocks airflow through an upstream side of the printhead opening in the closed state and allows airflow through the upstream side of the printhead opening in the open state
Data Source
AI summary
A printing system comprises a printhead to eject ink through an opening in a carrier plate to a deposition region. A print medium is held against a movable support surface by vacuum suction communicated through platen holes of a vacuum platen and transported through the deposition region. An airflow control system comprises upstream and downstream valves associated with the printhead, individually addressable channels for the vacuum platen, or both. The upstream and downstream valves are arranged to selectively block and allow airflow through an upstream side or a downstream side, respectively, of the opening in the carrier plate. Actuation of the upstream and downstream valves may be controlled based on a location of the print medium. The channels are arranged to selectively control the supply of vacuum suction to respectively corresponding columns of platen holes. Actuation of the channels may be controlled based on a size of the print medium.