Humidification Section for Image Transfer Stability
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining a proper transfer electric-field for recording media with low transferability, such as high-resistance papers, leading to transfer failures and image distortion due to abnormal discharges.
Innovation Solution
The apparatus includes a transfer section with a humidification system that selectively humidifies the recording medium based on its type, using a selection mechanism to choose between constant current or voltage control to maintain an appropriate transfer electric-field, ensuring stable image transfer by adopting a creeping transfer method for high-resistance papers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a strong transfer electric-field is applied to high-resistance recording media, then image transfer speed is improved, but abnormal discharges occur causing image distortion
Solution Approach 1:
The patent changes the electrical resistance parameter of the recording medium by controlling its humidity content. By adjusting the moisture level, the surface resistivity is modified to an optimal range that allows adequate image transfer without causing abnormal discharges, thus resolving the contradiction between transfer speed and discharge prevention
Solution Approach 2:
The patent introduces humidity control as an intermediary mechanism between the transfer electric-field and the recording medium. By using moisture as a mediator to adjust the electrical properties of the paper, the system achieves smooth charge distribution and prevents direct harmful interactions between strong electric fields and high-resistance media
2Reliability
If humidification is applied to all recording media, then transfer reliability is improved, but energy consumption increases and non-high-resistance media are unnecessarily treated
Solution Approach 1:
The patent applies humidification selectively only to high-resistance recording media that require it, rather than uniformly treating all media types. By identifying and targeting specific media with high surface resistivity, the system achieves improved transfer reliability only where needed, avoiding unnecessary energy consumption on already-suitable media
Solution Approach 2:
The patent implements a dynamic control system that adjusts humidification based on the measured electrical resistance characteristics of each recording medium. The system continuously monitors and adapts its humidification level to match the actual needs of the media, optimizing both reliability and energy efficiency
3Device complexity
If constant voltage control is used in the transfer section, then control simplicity is maintained, but transfer electric-field stability deteriorates when humidity varies
Solution Approach 1:
The patent performs preliminary humidification of the recording medium before the transfer process to pre-establish optimal electrical resistance characteristics. By preparing the media in advance with appropriate moisture content, the system ensures stable transfer electric-field conditions without requiring complex real-time control mechanisms during the actual transfer
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
This approach effectively maintains the transfer electric-field within a necessary range, preventing abnormal discharges and ensuring successful image transfer on papers with low transferability, like black paper or cardboard, by reducing surface resistivity through humidification.
Implementation Method 1
a humidification section (4) which is provided upstream of the transfer region TR in the direction of transport of the recording medium S and humidifies the recording medium S
Implementation Method 2
a transfer section (2) which includes a transfer member (2a) disposed in contact with an image holding surface of the image holding section (1) and an opposite member (2b) disposed at a position facing the transfer member (2a) across the image holding section (1), connects a transfer power supply (2c) to the opposite member (2b) so as to apply a transfer electric-field to a transfer region TR between the image holding section (1) and the transfer member (2a), and electrostatically transfers the image G held by the image holding section (1) onto a recording medium S transported to the transfer region TR
Data Source
AI summary
An image forming apparatus includes: an image holding section; a transfer section that has a transfer member, applies a transfer electric-field to a transfer region between the image holding section and the transfer member, and electrostatically transfers an image held by the image holding section onto a recording medium; contact sections that act as electrodes to ground while being in contact with the recording medium; a humidification section that is provided upstream of the transfer region and humidifies the recording medium; a first control section that performs control without humidification by the humidification section; a second control section that performs control to cause the humidification section to humidify the recording medium; and a selection section that selects the first control section or the second control section depending on a type of the recording medium.