Making
Electrostatic Sheet Stapler
Functional sheet materials including printed electronic circuits will be a main stream of logistics tag, IC tag and so on. Electrostatic sheet stapler can staple the functional sheet materials onto a target by electrostatic force. Both positive and negative charges are supplied to the sheet so that the net charges on the sheet becomes zero. Charge elimination for removing the sheet can be done easily by switching the voltage source.
Electrostatic Particle handler
Mechanical handling for small amount of particles are difficult because of electrostatic and/or mechanical force acting between the particles. Electrostatic particle handler catches small amount of particles less than 1 mg on the special electrode by electrostatic forces. The particles can be removed by special charge neutralizers and vibrators.
Compact super heated steam maker
Super heated steam is usually made by heating saturated water vapor. The system is composed by a boiler to make saturated water vapor and by the heater. Because the water vapor can be supplied to the heater without cooling, super heated steam maker setup is usually fixed at the required space including heavy boiler and rigid water vapor pipes. We are developing super heated steam maker directly produce super heated steam from liquid water using corona discharge and arc discharge. Water vapor is produced inside the hot cylindrical electrode heated by arc discharge. The vapor is charged by corona discharge so that the vapor can be attracted to the hot cylindrical electrode. 260 degree vapor can be produced at 17L/min
Sensing
Non contact surface resistivity sensor
Non contact surface resistivity sensor has been developed by a corona charger and surface voltmeter. A test target is partially charged by the corona charger along with the measurement of surface potential around the charged area. The surface potential rise time is a function of surface resistivity. The surface resistivity over than 10 to the 9th power ohm can be measured.
The surface resistivity of polymer materials are within the measurement range of this sensor. Degraded polymer by ultraviolet ray or plasma have lower surface resistivity because of introduction of hydrophobic species which can easily attach ambient water vapor. The change in wettability can be monitored by sensing the surface resistivity. We observed relationship between the wettability (contact angle) and surface resistivity for silicon rubber.
Non contact volume resistivity sensor
In electrostatic paint for plastic material, the plastic material firstly covered by conductive pre-coating for grounding. For checking the thickness of paint on the pre-coating, an electromagnetic thickness sensor can not be used because of low eddy current flowing into the pre-coating. Only destructive measurement, making cross section of paint by V cut and macroscopic viewing of the cut, is used so far. We are developing the thickness sensor that measures surface potential of paint charged by corona discharge. We found there is linear relationship between thickness of the paint and the surface potential. The measurement range is less than 200 microns. The degree of cure of the paint also can be measured because the surface potential of the paint is a function of volume resistivity of the paint.
Eliminating
EFD ionizer
Commercial electrostatic charge elimination system supplies positive and negative ions produced from high voltage needles with an air flow. The charge elimination speed depends on the velocity of air flow. We develops charge elimination system (Ionizer) without air flow using special arrangement of electrodes. An electric field between the ionizer and the charged target can convey ions to the target, so called Electrostatic Field Driven (EFD). The residual target potential is less than 1 V.
Passive ionizer
Static charges can be eliminated by just placing a grounded needle close to the target if the electric field at the tip of the needle meet a corona inception condition. These ionizer is called passive type. We found an air assist for the passive ionizer can enhance the charge elimination ability. Also we can monitor the charge amount of the target by measuring the discharge current from the passive ionizer. Optimizing air assist and understanding property as the charge sensor are ongoing.