A charge electrode structure for electrostatic ink jet systems comprises a series of dielectric laminates having planar electrode laminates therebetween and openings therethrough for passage of the ink jet stream approximately normal to the plane of the electrodes. The electrodes for the same stream are electrically interconnected and energizeble to form a charging field similar to that of a tubular charge electrode parallel to the stream.
An ink jet recorder has a means for forming streams of ink drops and a means for selectively charging the drops in the streams as they are formed. The drops pass through charge ring orifices which are lined with charge rings. Charging potentials are selectively applied to the charge rings to induce selectively charges in the drops as they are formed. In order to prevent a large deplating current from flowing between the charge rings in the event of an inadvertent short, a means for limiting current flow is provided. Current may be limited by a charge ring formed from a bulk resistive material such as an epoxy filled with conductive particles. Alternatively, current may be limited by discrete resistors positioned adjacent the charge rings and through which the charging potential is applied.
A charge plate fabrication process provides a charge plate assembly having minimal distortion caused by shifts in temperature and humidity. The fabrication process includes the steps of forming a charge plate coupon having a plurality of charging electrodes and electrical connections on an etchable substrate and providing a ceramic charge plate substrate. An adhesive layer is then applied between the charge plate coupon and the charge plate substrate before assembling the charge plate coupon and the charge plate substrate in a fixture. Finally, the assembly is cured in the fixture.
A charge electrode structure assembly wherein an electrode pattern is coated on a dielectric substrate over which it is coated by a sealing layer of an insulating solder glass adapted to fusion bond to a second superimposed dielectric substrate. The solder glass is formed from a composition comprised of by weight, 56% SiO.sub.2, 8% Al.sub.2 O.sub.3, 8% B.sub.2 O.sub.3, 6% BaO, 6% PbO, 6% Na.sub.2 O, 4% ZrO.sub.2, 3% Li.sub.2 O and 3% La.sub.2 O.sub.3.
A charge electrode assembly useful in an ink jet printer comprises a nonconductive supporting structure in which a multiplicity of grooves are formed. Each groove has a conductive layer of a corrosion-resistant noble metal, preferably platinum or rhodium, thereby forming an electrode. An electric power supply is coupled to the electrodes and energizes selected ones of the electrodes when propelled ink droplets traverse the electrode area.
A charge electrode array for a multi-nozzle ink jet array is fabricated from alternate layers of stainless steel and epoxy resin. The charge electrode array may be formed by positioning stainless steel tabs in previously grooved nonconductive substrate such as ceramic. The grooves are spaced sufficiently apart to allow insulating material to be placed between each stainless steel tab. Alternatively, a stainless steel plate may be bonded to a nonconductive substrate. Then the stainless steel can be sliced so that insulating material can be placed between each stainless steel strip. Epoxy fills the gap between tabs or strips forming an insulating layer. An ink drop charging channel through each tab or strip is formed by drilling through the tips of the steel tabs or strips, or by cutting U-shaped channels through the tips of the tabs or strips.
