Electrode Current Sensing for Toner Transfer Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image formation apparatuses face challenges in accurately setting transfer conditions for toner images on recording media due to limitations in sensing paper properties, such as capacitance and resistance, leading to inconsistent transfer biases and increased costs with the use of sensors.
Innovation Solution
An image formation apparatus with a first electrode portion and a second electrode portion, along with sensing units to measure currents flowing through the media, allows for the accurate estimation of paper properties and setting of transfer conditions based on sensed currents, reducing the need for additional sensors and improving transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is mounted to sense physical properties of paper, then transfer bias can be set in accordance with sensing information, but cost for sensing increases and space for installation is required
Solution Approach 1:
The patent applies multi-functionality by making the transfer electrode perform both transfer function and sensing function. The same electrode structure used for toner transfer is also used to measure current, eliminating the need for separate sensors. This resolves the contradiction by achieving paper property measurement without adding sensor complexity or installation space requirements.
Solution Approach 2:
The system uses itself for measurement by utilizing the transfer current that naturally flows during the transfer process to infer paper electrical properties. No external sensing device is needed as the transfer electrode and current measurement system serve the dual purpose of both transferring toner and characterizing paper properties.
2Ease of operation
If transfer bias is set based on user-set paper information, then convenience is improved, but appropriate transfer bias cannot be set when user cannot determine or does not set paper information
Solution Approach 1:
The system implements feedback by measuring the actual current during transfer and using this information to adjust and determine the appropriate transfer bias. The control unit receives current measurement results and automatically sets optimal transfer conditions, creating a closed-loop system that ensures reliable transfer bias setting regardless of user input.
Solution Approach 2:
The patent replaces the manual mechanical system of user paper type selection with an electrical measurement system. Instead of relying on user input about paper properties, the system electrically measures current characteristics to automatically determine paper electrical properties and set appropriate transfer bias.
3Device complexity
If transfer current alone is used to estimate paper properties, then simplicity is maintained, but accurate distinction between high resistance and low capacitance cannot be made when current is low
Solution Approach 1:
The patent segments the measurement process into two distinct current measurements: transfer current (flowing through paper during transfer) and discharged current (flowing from charged paper to second electrode). This segmentation allows separate measurement of electrical resistance effects and capacitance effects, enabling accurate distinction between high resistance and low capacitance conditions that cannot be differentiated using transfer current alone.
4Device complexity
If discharged current is used to estimate paper properties with constant voltage control, then measurement is simplified, but secondary transfer current variation causes discharged current variation making proper voltage setting difficult
Solution Approach 1:
The patent segments the measurement into two distinct current components measured at different stages: transfer current measured during the transfer process, and discharged current measured after transfer when charges move to the second electrode. This temporal and functional segmentation separates the measurement of resistance-related current from capacitance-related current, enabling accurate paper property estimation despite variations in secondary transfer current.
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 solution enables precise setting of transfer conditions, enhancing the accuracy and efficiency of toner image transfer while reducing costs and complexity by utilizing existing electrode structures and current sensing technology.
Implementation Method 1
a first sensing unit configured to sense a first current which flows to the first electrode portion as a result of application of a voltage across the contact electrode and the counter electrode
Implementation Method 2
a second sensing unit configured to sense a second current which flows from the charged recording medium to the second electrode portion
Implementation Method 3
In transfer of a toner image to paper in an electrophotographic process, in general, a bias is applied across an image carrier or an intermediate transfer element and paper so that toner is transferred owing to static electricity
Data Source
AI summary
An image formation apparatus includes a first electrode portion including a contact electrode and a counter electrode, a second electrode portion arranged as not being in contact with a recording medium, a first sensing unit configured to sense a first current which flows to the first electrode portion as a result of application of a voltage across the contact electrode and the counter electrode while the recording medium lies between the contact electrode and the counter electrode, a second sensing unit configured to sense a second current which flows from the charged recording medium to the second electrode portion, and a control unit. The control unit sets a transfer condition for transferring a toner image to the recording medium based on the first current sensed by the first sensing unit and the second current sensed by the second sensing unit.