Liquid Ejecting Apparatus Static Charge Control
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Solution Overview
Problem
Ink jet recording apparatuses face issues with foreign objects like paper dust sticking to the nozzle surface due to static charging, leading to ejection problems, as existing techniques like using a discharging brush can exacerbate the issue by producing more dust.
Innovation Solution
A liquid ejecting apparatus with a transport unit, a liquid ejecting head, a carriage, a charge amount detection unit, and a driving control unit that adjusts transport speed, carriage position, and a discharging mechanism to reduce static charge on the recording medium, preventing foreign objects from sticking to the nozzle surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discharging brush is used to remove foreign objects from the recording medium surface, then foreign objects are removed, but paper dust is produced which sticks to the nozzle surface causing ejection problems
Solution Approach 1:
The patent replaces the mechanical discharging brush system with an electrostatic-based system. A charge detection unit detects the charge amount on the recording medium, and a discharge brush with opposite polarity is used to neutralize the charge rather than mechanically brush the surface. This substitution eliminates paper dust generation while maintaining the ability to prevent foreign object adhesion to the nozzle.
Solution Approach 2:
The patent introduces an intermediary electrostatic field between the recording medium and the nozzle. By detecting the charge amount and applying a discharge brush with opposite polarity, the system creates an electrostatic intermediary that prevents foreign objects from adhering to the nozzle surface without requiring direct mechanical contact that would generate dust.
2Reliability
If the transport speed of the recording medium is reduced, then the charge amount on the recording medium is reduced, but the productivity of the liquid ejecting apparatus decreases
Solution Approach 1:
The patent applies preliminary action by detecting the charge amount on the recording medium before it reaches the nozzle area. When high charge is detected, the discharge brush is activated in advance to neutralize the charge, preventing foreign object adhesion before it becomes a problem. This allows the transport speed to be maintained at normal levels without sacrificing reliability.
Solution Approach 2:
The patent implements periodic action by continuously monitoring the charge amount on the recording medium and periodically activating the discharge brush only when high charge is detected. This selective, periodic operation maintains productivity by keeping the transport speed high during normal conditions while periodically neutralizing charge when necessary to prevent foreign object adhesion.
3Reliability
If the carriage moves back and forth to reposition the liquid ejecting head, then foreign objects are prevented from sticking to the nozzle, but the operation complexity increases
Solution Approach 1:
The patent uses an electrostatic field as an intermediary to prevent foreign object adhesion, eliminating the need for complex carriage movements. The discharge brush with opposite polarity creates an electrostatic barrier that prevents charged foreign objects from reaching the nozzle, simplifying the operation while maintaining reliability.
Solution Approach 2:
The patent replaces the mechanical carriage movement system with an electrostatic discharge system. Instead of moving the carriage back and forth to prevent foreign object adhesion, the system uses a discharge brush to neutralize charges on the recording medium, providing a simpler, more direct solution that maintains reliability without operational complexity.
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 foreign objects from sticking to the nozzle surface, ensuring reliable and precise liquid ejection by managing the charge amount on the recording medium and positioning the nozzle to avoid high-static areas.
Implementation Method 1
a charge amount detection unit that detects a charge amount on the recording medium
Implementation Method 2
drives a discharging mechanism that discharges a contact portion of the transport unit that comes into contact with the recording medium
Implementation Method 3
a liquid ejecting head that ejects a liquid from a nozzle onto the recording medium transported by the transport unit
Data Source
AI summary
A liquid ejecting apparatus includes: a transport unit that transports a recording medium; a liquid ejecting head that ejects a liquid onto the recording medium; a carriage that holds the liquid ejecting head; a charge amount detection unit that detects a charge amount on the recording medium; and a driving control unit. In the case where the charge amount detected by the charge amount detection unit has exceeded a predetermined value, the driving control unit performs at least one of the following: controls the transport unit so that the transport speed of the recording medium becomes relatively slower.