Electrostatic Charging Apparatus for Sheet Transport Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sheet transport systems for inkjet printers, such as vacuum belt systems and roller nips, face issues like air currents disturbing ink flow, paper lifting or curling, and unwanted movement, leading to image distortion and paper jams, especially in high-speed printing and marginless printing applications.
Innovation Solution
An electrostatic charging apparatus using a Mylar belt and a charging roller to electrostatically tack paper sheets to the belt, maintaining precise spacing and reducing ink mist by balancing surface charges with a neutralizing circuit, ensuring stable paper transport and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum belt systems are used for sheet transport, then sheets can be held and transported through the print zone, but air currents develop that disturb ink flow and cause image distortion
Solution Approach 1:
The patent replaces the vacuum mechanical system with an electrostatic system. Instead of using vacuum pressure to hold sheets, the invention uses electrostatic charges applied to the sheet surface and corresponding charges on the belt to create holding force. This substitution eliminates the air currents generated by vacuum systems while maintaining reliable sheet transport through the print zone.
Solution Approach 2:
The patent introduces electrostatic charges as an intermediary mechanism between the sheet and the transport belt. By applying opposite polarity charges to the sheet and belt surfaces, the system creates an electrostatic attraction that holds the sheet in place without requiring vacuum pressure, thereby eliminating the harmful air currents while maintaining transport stability.
2Reliability
If roller nips are used to hold sheets, then sheets can be transported, but sheets experience lifting or curling and unwanted movement
Solution Approach 1:
The patent replaces mechanical roller nips with an electrostatic holding system. Instead of using mechanical pressure from rollers that can cause sheet deformation, the invention uses electrostatic attraction between charged surfaces to hold the sheet flat and stable throughout transport, eliminating lifting and curling issues.
Solution Approach 2:
The patent introduces electrostatic charges as an intermediary force to replace mechanical roller contact. The electrostatic field acts as a distributed holding force across the sheet surface without concentrated mechanical pressure points, preventing sheet curling and maintaining flat transport through the printing process.
3Productivity
If high-speed printing is implemented, then productivity increases, but paper jams and image distortion occur due to unstable sheet transport
Solution Approach 1:
The patent replaces mechanical vacuum and roller systems with electrostatic charging mechanisms that provide more stable sheet holding at high speeds. The electrostatic forces maintain consistent sheet-belt adhesion throughout the print zone even at elevated transport velocities, preventing paper jams and image distortion while enabling high-speed operation.
Solution Approach 2:
The patent changes the fundamental parameter of sheet holding from mechanical pressure (vacuum or roller contact) to electrostatic attraction. This parameter change allows for speed-independent holding force, maintaining sheet stability across a wide range of transport speeds including high-speed operation, thereby improving both productivity and reliability simultaneously.
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 solution effectively prevents paper jams and image distortion by maintaining precise paper alignment and ink flow, allowing for high-speed, marginless printing with accurate registration of multiple images.
Implementation Method 1
a charge supply circuit operable to charge the Mylar belt to a potential sufficient to electrostatically tack a paper sheet to the Mylar belt
Implementation Method 2
a neutralizing circuit connected to the Mylar belt and operable to reduce the electric field adjacent the Mylar belt
Data Source
AI summary
A media sheet drive has a continuous belt of a dielectric material for transporting sheet media supported on the belt in a transport direction. A launch mechanism is used to launch a sheet medium onto a top surface of the belt. A charging circuit including a charging roller is used to charge a top surface of the sheet medium and the belt as the sheet medium is launched. Charging acts to generate an electrostatic tacking force to tack the sheet medium to the belt. The charging roller has a second function to smooth out curled edges of paper as it is acted on by the charging circuit so that the full extent of a launched sheet medium may be subject to the electrostatic tacking force.