Electrostatic Attraction Device for Inkjet Sheet Conveyance
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Solution Overview
Problem
Ink-jet printers face instability in sheet conveyance due to insufficient electrostatic attractive force, leading to reduced electric current and Johnsen-Rahbeck force, causing issues with sheet attraction and conveyance.
Innovation Solution
A recording apparatus with an attraction device featuring comb-like electrodes and a pressing mechanism using conductive rollers to increase the attractive force by applying different potentials to the electrodes and pressing the recording medium onto the conveyor belt, enhancing the electrostatic attraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the convey roller is disposed upstream of the electrostatic-attractive-force generating means, then the sheet is pressed onto the conveyor belt, but the sheet cannot be sufficiently attracted to the conveyor belt by the electrostatic-attractive-force generating means
Solution Approach 1:
The pressing device presses the sheet onto the conveyor belt before the sheet enters the electrostatic-attractive-force generating means. This preliminary action ensures that the sheet is in good contact with the conveyor belt when the electrostatic attraction is applied, allowing the attraction force to effectively act on the sheet without interference from the pressing action.
Solution Approach 2:
The patent divides the sheet conveyance process into distinct functional zones: a pressing zone where the pressing device applies mechanical force to contact the sheet with the conveyor belt, and an attraction zone where the electrostatic-attractive-force generating means applies electrical attraction. This segmentation allows each mechanism to perform its function optimally without interfering with the other.
2Ease of operation
If a clearance is generated between the sheet and the conveyor belt, then the sheet can be separated from the conveyor belt, but the clearance functions as a large electric resistance reducing the electric current and Johnsen-Rahbeck force
Solution Approach 1:
The pressing device performs a preliminary action by pressing the sheet onto the conveyor belt before the sheet enters the attraction zone. This ensures that the sheet is in good electrical contact with the conveyor belt when the electrostatic attraction is applied, minimizing clearance and reducing electrical resistance.
Solution Approach 2:
The pressing device acts as an intermediary mechanism that ensures proper contact between the sheet and conveyor belt. By applying mechanical pressure, it eliminates air gaps and ensures good electrical contact, thereby reducing resistance and allowing sufficient current to flow for effective electrostatic attraction.
3Reliability
If the attractive force is increased to prevent sheet floating, then sheet conveyance stability is improved, but the device complexity increases
Solution Approach 1:
The pressing device serves multiple functions: it presses the sheet onto the conveyor belt for mechanical support, and it simultaneously ensures good electrical contact for electrostatic attraction. The comb-like electrodes also serve dual purposes by generating electrostatic attraction and by their geometric shape optimizing the electric field distribution.
Solution Approach 2:
The patent optimizes the geometric parameters of the comb-like electrodes, including the spacing between teeth, the length of extending portions, and the overall electrode configuration. These parameter optimizations allow the electrostatic-attractive-force generating means to generate sufficient attraction force with a relatively simple structure.
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 significantly increases the attractive force, stabilizing sheet conveyance, preventing jams and floating, and improving attraction efficiency across the entire sheet, ensuring reliable conveyance and effective image formation.
Implementation Method 1
an attraction device which is disposed at a position where the conveyor belt is interposed between the attraction device and the recording head and which includes (a) a first electrode having a plurality of first extending portions each of which extends so as to be longer than the recording head in the medium conveyance direction and (b) a second electrode having a plurality of second extending portions each of which extends so as to be longer than the recording head in the medium conveyance direction, each of the plurality of first extending portions and each of the plurality of second extending portions being alternately arranged in a perpendicular direction that is perpendicular to the medium conveyance direction, the attraction device being configured to permit the conveyor belt to generate an attractive force to attract the recording medium to the conveyor belt by giving mutually different potentials to the first electrode and the second electrode
Implementation Method 2
a pressing device including a contact member which has electrical conductivity and which is disposed at a position where the contact member is opposed to respective upstream sections of the plurality of first extending portions and the plurality of second extending portions, which sections are located on an upstream side of the recording head in the medium conveyance direction, the contact member being configured to contact the recording medium placed on the conveyor belt, the pressing device being configured to press the recording medium onto the conveyor belt by the contact member
Data Source
AI summary
A recording apparatus for forming an image on a recording medium, including: a recording head; a conveyor belt to convey the medium in a conveyance direction; an attraction device including a first electrode having first extending portions and a second electrode having second extending portions and configured to permit the belt to generate an attractive force to attract the medium to the belt by giving mutually different potentials to the first and second electrodes; and, a pressing device including a contact member having electrical conductivity and disposed at a position where the contact member is opposed to respective upstream sections of the first and second extending portions, which upstream sections are located on an upstream side of the head in the conveyance direction, the contact member being configured to contact the medium placed on the belt, the pressing device being configured to press the medium onto the belt by the contact member.